Mux configuration
From IGEP - ISEE Wiki
Contents
Overview
This How-To is meant to be a starting point for people to learn configure mux for IGEP v2 devices as quickly and easily as possible. For this how-to i used Linaro Headless and Ubuntu 10.04 with Linaro Toolchain.
Mux (or multiplexer) is a Omap peripheral that can be controlled via software. Its function is connect other peripherals to some available Omap pins.
Each pin is configurable by software using its associated pad configuration register field, which is 16 bits wide:
|
One pad configuration register field is available for each pin. Each 32-bit pad configuration register is grouped into two 16-bit pad configuration register fields. One pad configuration register provides control for two different pins. These registers can be accessed using 8, 16 and 32 bits operations.
The functional bits of a pad configuration register field are divided into the following five fields:
• MUXMODE (3 bits) defines the multiplexing mode applied to the pin. A mode corresponds to the selection of the functionality mapped on the pin with six (0 to 5) possible functional modes for each pin.
• PULL (2 bits) for combinational pullup/pulldown configuration:
-> PULLTYPESELECT: Pullup/pulldown selection for the pin.
-> PULLUDENABLE: Pullup/pulldown enable for the pin.
• INPUTENABLE (1 bit) drives an input enable signal to the I/O CTRL.
• Off mode values (5 bits) override the pin state when the OFFENABLE bit CONTROL. This feature is used for power saving management:
->OFFENABLE: Off mode pin state override control. Set to 1 to enable the feature and to 0 to disable it.
->OFFOUTENABLE: Off mode output enable value. Set to 0 to enable the feature and to 1 to disable it.
->OFFOUTVALUE: Off mode output value.
->OFFPULLUDENABLE: Off mode pullup/pulldown enable.
->OFFPULLTYPESELECT: Off mode pullup/pulldown selection.
• Wake-up bits (2 bits):
->WAKEUPENABLE: Enable wake-up detection on input. It is also the off mode input enable value.
->WAKEUPEVENT: Wake-up event status for the pin.
NOTE: Off mode can be configured like pin output with a HIGH or LOW value or pin input with wake-up detection feature.
NOTE: For input pins, OFFOUTENABLE and OFFOUTVALUE bits can not be configured.
|
|
Mode selection
| MUXMODE | Select Mode |
| 0b000=0 | Mode 0 (Primary mode) |
| 0b001=1 | Mode 1 (Possible mode) |
| 0b010=2 | Mode 2 (Possible mode) |
| 0b011=3 | Mode 3 (Possible mode) |
| 0b100=4 | Mode 4 (Possible mode) |
| 0b101=5 | Mode 5 (Possible mode) |
| 0b110=6 | Mode 6 (Possible mode) |
| 0b111=7 | Mode 7 (Safe Mode) |
Mode 0 is the primary mode. When mode 0 is set, the function mapped to the pin corresponds to the name of the pin.
Mode 1 to mode 6 are possible modes for alternate functions. On each pin, some modes are used effectively for alternate functions, while other modes are unused and correspond to no functional configuration.
The safe mode (default mode 7) avoids any risk of electrical contention by configuring the pin as an input with no functional interface mapped to it. The safe mode is used mainly as the default mode for all pins containing no mandatory interface at the release of power-on reset.
NOTE: For most pads, the reset value for the MUXMODE field is 0b111. The exceptions are pads to be used at boot time to transfer data from selected peripherals to the external flash memory.
Pull Selection
Note: when a pin is in output mode, pulls are automatically disable.
| PULLTYPESELECT | PULLUDENABLE | Pin Behavior |
| 0b0 | 0b0 | Pull-down selected but not activated |
| 0b0 | 0b1 | Pull-down selected and activated if pin is NOT configured as OUTPUT |
| 0b1 | 0b0 | Pull-up selected but not activated |
| 0b1 | 0b1 | Pull-up selected and activated if pin is NOT configured as OUTPUT |
Input Enable
INPUTENABLE = 0: Input Disable. Pin is configured in output only mode.
INPUTENABLE = 1: Input Enable. Pin is configured in bidirectional mode.
NOTE: For proper functioning of some peripherals INPUTENABLE must be set to 1 for pads configured to drive output clocks:
- SDRC
- GPMC
- McSPIi
- I2Ci
- MMCi
- McBSPi
- HSUSB HOST
Off mode values and Wake-up
This mode is used to disable some pins and reduce low power consumption.
Please contribute ..
IGEP
Important tips
Use the following tips to configure mux without problems:
- Mux can connect multiple connectors at the same peripheral, this improper use can damage the processor. Make sure to disable old connector configuration before use new one.
- Some peripherals can only be used placing or replacing some resistances. View schematics for more information.
- Some connectors can be shared with multiple peripherals. If you don't use them you should disable them. For example: you need to disable OMAP if you want control wifi module with other IC via J990 or disable Bluetooth to use UART2 via J990.
Configure mux
IgepV2 Board have a default mux configuration, but some cases is necessary change it, for example your project need UART2 at j990 connector to transmit data, for this purpose you need change some mux configurations to enable it and be sure that this modification don't break or interferes in other IC or peripherals. The mux options are vast. There are three ways to configure mux at DM37xx and OMAP35xx:
- Editing OS User Space. this mode has a issue, when your system reboot or shutdown you will need to configure again. Example.
- Using kernel buddies. This way is ot avaliable in some cases. Example.
- Editing and compile kernel sources. Example.
More information about mux.
Feedback and Contributing
At any point, if you see a mistake you can contribute to this How-To.
Available peripherals on external connector
The next tables show you all the mux capabilities:
J990 connector
-There are some peripherals than can be connected to J990 like mm3 and camera, but is not used in this how-to.
-High Speed USB 3 is only available on Omap 3530 in the next pads:
3: HSUSB3_TLL_NXT
4: HSUSB3_TLL_D4
5: HSUSB3_TLL_DIR
6: HSUSB3_TLL_D6
7: HSUSB3_TLL_STP
8: HSUSB3_TLL_D7
10: HSUSB3_TLL_D5
| Pad: | Connect to: |
Default peripheral (mode=0) |
Default function: | Other available peripherals: | Share with: |
| 1 | VIO 1V8 | - | Power 1v8 | - | - |
| 2 | DC 5V | - | Power 5v | - | - |
| 3 | MMC2_DAT7 | MMC2_DAT7 | Reset Wlan |
MMC2_CLKIN(mode=1) MMC3_DAT3(mode=3) GPIO_139(mode=4) |
Wlan: This pad can reset Wlan peripheral using Omap GPIO low level (GND). If you reset continuously Wlan all their pads are in High Impedance. Also you can disable Wlan from J990 low level. Omap: protect Omap pad if you don't use it.(1)
|
| 5 | MMC2_DAT6 | MMC2_DAT6 | Power down Wlan |
MMC2_DIR_CMD(mode=1) MMC3_DAT2(mode=3) GPIO_138(mode=4) |
Wlan: This pad can power down Wlan peripheral using Omap GPIO low level (GND), power up removing GND. Also you can power down Wlan from J990 low level. Omap: protect Omap pad if you don't use it.(1)
|
| 7 | MMC2_DAT5 | MMC2_DAT5 | Reset Bluethoot |
MMC2_DIR_DAT1(mode=1) MMC3_DAT1(mode=3) GPIO_137(mode=4) |
Bluethoot: This pad can reset Bluethoot
peripheral using Omap GPIO low level (GND). If you reset continuously Bluethoot all their pads are in High Impedance. Also you can disable Bluethoot from J990 low level.Omap: protect Omap pad if you don't use it.(1) |
| 9 | MMC2_DAT4 | MMC2_DAT4 | - |
MMC_DIR_DAT0(mode=1) MMC3_DAT0(mode=3) GPIO136(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 11 | MMC2_DAT3 | MMC2_DAT3 | Transfer data between Omap and Wlan |
McSPI3_CS0(mode=1) GPIO_135(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 13 | MMC2_DAT2 | MMC2_DAT2 | Transfer data between Omap and Wlan |
McSPI3_CS1(mode=1) GPIO_134(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 15 | MMC2_DAT1 | MMC2_DAT1 | Transfer data between Omap and Wlan | GPIO_133(mode=4) | Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 17 | MMC2_DAT0 | MMC2_DAT0 | Transfer data between Omap and Wlan |
McSPI3_SOMI(mode=1) GPIO_132(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 19 | MMC2_CMD | MMC2_CMD | Control Wire for bus MMC2 (Wlan) |
McSPI3_SIMO(mode=1) GPIO_131(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 21 | MMC2_CLK0 | MMC2_CLK | Clock for MMC2 (Wlan) |
McSPI3_CLK(mode=1) GPIO_130(mode=4) |
Wlan: Protect Wlan if you don' use it. See MMC2_DAT7 pad. Omap: protect Omap pad if you don't use it.(1)
|
| 4 | MCBSP3_DX | MCBSP3_DX | Transmitted serial Data (Bluethoot audio) |
UART2_CTS(mode=1) GPIO_140(mode=4) |
TPS65950: disable it via kernel (2) If you don't use it.
|
| 6 | MCBSP3_CLKX | MCBSP3_CLKX | Transmitted serial Clock (Bluethoot audio) |
UART2_TX(mode=1) GPIO_142(mode=4) |
Bluethoot: Protect Bluethoot if you don' use it. See MMC2_DAT5 pad. TPS65950: disable it via kernel (2) If you don't use it.
|
| 8 | MCBSP3_FSX | MCBSP3_FSX | Transmited Frame Syncronisation (Bluethoot audio) |
UART2_RX(mode=1) GPIO_143(mode=4) |
Bluethoot: Protect Bluethoot if you don' use it. See MMC2_DAT5 pad. TPS65950: disable it via kernel (2) If you don't use it.
|
| 10 | MCBSP3_DR | MCBSP3_DR | Received Serial Data (Bluethoot audio) |
UART2_RTS(mode=1) GPIO_141(mode=4) |
TPS65950: disable it via kernel (2) If you don't use it.
|
| 12 | MCBSP1_DX | MCBSP1_DX | Transmited serial Data (not used) |
McSPI4_SIMO(mode=1) McBSP3_DX(mode=2) GPIO_158(mode=4) |
- |
| 14 | MCBSP1_CLKX | MCBSP1_CLKX | Transmited serial clock (not used) |
McBSP3_CLKX(mode=2) GPIO_162(mode=4) |
- |
| 16 | MCBSP1_FSX | MCBSP1_FSX | Transmited Frame Syncronization (not used) |
McSPI4_CS0(mode=1) McBSP3_FSX(mode=2) GPIO_161(mode=4) |
- |
| 18 | MCBSP1_DR | MCBSP1_DR | Received Serial Data (not used) |
McSPI4_SOMI(mode=1) McBSP3_DR(mode=2) GPIO_159(mode=4) |
- |
| 20 | MCBSP1_CLKR | MCBSP1_CLKR | Received Clock (not used) |
GPIO_156(mode=4) |
- |
| 22 | MCBSP1_FSR | MCBSP1_FSR | Received frame syncronization (not used) |
GPIO_157(mode=4) |
- |
| 23 | I2C2_SDA | I2C2_SDA | I2C Data |
GPIO_183(mode=4) |
Cam connector: Check and RC14 is not welded or don't use it.
|
| 24 | I2C2_SCL | I2C2_SCL | I2C Clock |
GPIO_168(mode=4) |
Cam connector: Check and RC13 is not welded or don't use it. |
| 25 | REGEN | - | Master/Slave control power TPS65950 |
- | - |
| 26 | nRESET | - | Read Reset Omap | - | - |
| 27 | GND | - | GND | - | - |
| 28 | GND | - | GND | - | - |
(1): To protect Omap pads from external signals, configure Mux in mode=7 (safe_mode). With this mode, buffer is configured in high impedance
(2): Disable TPS65950 go to file sound/soc/codecs/twl4030.c change line 54 Code:
0x00, /* REG_VOICE_IF (0xF) */
to Code:
0x04, /* REG_VOICE_IF (0xF) */
J960 connector
J960 connector can not use mux capabilities, because this connector is dedicated to use RS232 comunication. Default hardware/software configuration is:
| Pad | Connect to: | Default periphera: | Other peripheral: | Share with: |
Default function: |
| 1 | - | - | - | - |
|
| 2 | RS232_RX2 | UART3_RX | UART2_RX | - |
Kernel console params(4) |
| 3 | RS232_TX2 | UART3_TX | UART2_TX | - |
Kernel console params(4) |
| 4 | - | - | - | - |
- |
| 5 | GND | - | - | - |
- |
| 6 | GND | - | - | - |
- |
| 7 | - | - | - | - |
- |
| 8 | RS232_TX1 | UART1_TX | UART3_TX | RS485 interface(5) |
- |
| 9 | RS232_RX1 | UART1_RX | UART3_RX | RS485 interface(5) |
- |
| 10 | - | - | - | - |
- |
- Other peripherals can be configured via hardware, placing/replacing some resistances. See IGEPv2 Schematic for more information.
(4): To set other functionalities to UART3 (/dev/ttyS2) edit igep.ini file:
Search line:
console=ttyS2,115200n8
Replace by:
; console=ttyS2,115200n8
(5): Allows to use UART1 as RS232 instead of EI485, edit igep.ini:
Search line:
board.ei485=yes
Replace by:
board.ei485=no
J400 connector
J400 is used to JTAG (Joint Test Action Group). JTAG is a standardized serial protocol widely used in printed circuit boards. Its main functions are:
-Debug the software of an embedded system directly
-Storing firmware
-Boundary scan testing
More information: http://es.wikipedia.org/wiki/JTAG.
Only Pad 13 and 14 have mux capabilities, for example you can use them like GPIO(mode=4). More information in IGEPv2 Schematic.
J970 connector
This connector don't have mux capabilities.
J970 is used to implement a keypad. It is controlled by TPS65950, this method avoid reduce Omap proces capabilities. TPS65950 send via I2C1 all the interrupt request. Their characteristics are:
- Can handle up to 8 x 8 keypads, IGEPv2 can handle up to 4 x 4 keypads.
- Optionally, you can decode via Omap software.
- Event detection on key press and key release.
- Multikey press detection, can detect up 2 keys at the same time.
- Long-key detection on prolonged key press.
- Programmable time-out on permanent key press or after keypad release.
More information in TPS65950 datasheets.
JC30 connector
JC30 is used to connect a camera for capture video or image. Omap have the processing capability to connect RAW image-sensor modules via this connector.
There are some peripherals than can be connected to JC30 like like CAM, SSI and CSI, but is not used in this how-to. GPIO are the default peripheral.
Before use this connector be careful at these points:
- Pad 1 can be used to power down wifi module if RD41 is short circuit, replace RD42 for this porpouse.
- Pad 2 can be used to reset wifi module if RD43 is short circuit, replace RD44 for this porpouse.
- Pad 21 can be connected to I2C2_SCL, that wire is shared with J990 connector and I2C2_SCL peripheral. Placing/replacing RC13 for tis porpouse.
- Pad 22 can be connected to I2C2_SDA, that wire is shared with J990 connector and I2C2_SDA peripheral. Placing/replacing RC14 for tis porpouse.
JA42 connector
JA42 is used for DVI (Digital Video Interface) control part, TouchScreen control and SPI1.
-There are some peripherals than can be connected to JA42 like MM3, MM2, SSI, USB and HW_DBG, but is not used in this how-to.
Some pads have mux capabilities:
| Pad: | Connect to: |
Default peripheral (mode=0) |
Default function: | Other available peripherals: | Share with: |
| 1 | VIO 1V8 | - | Power 1v8 | - | - |
| 2 | SYS_BOOT5 |
SYS_BOOT5 |
Omap boot config |
MMC2_DIR_DAT(mode=1) GPIO_7 (mode=4) |
- |
| 3 | DC_5V | - | Power 5v | - | -
|
| 4 | GND | - | GND | - | -
|
| 5 | SYS_BOOT0 |
SYS_BOOT0 |
Omap boot config |
GPIO_2 (mode=4) |
- |
| 6 | SYS_BOOT1 |
SYS_BOOT1 |
Omap boot config |
GPIO_3 (mode=4) |
- |
| 7 | DVI_VSYNC | DSS_VSYNC | LCD vertical sync (Expansion) |
GPIO_68(mode=4) |
TFP410 (6)
|
| 8 | DVI_HSYNC | DSS_HSYNC | LCD Horitzontal sync (Expansion) |
GPIO_67 (mode=4) |
TFP410 (6) |
| 9 | DVI_ACBIAS | DSS_ACBIAS | LCD Control (Expansion) | GPIO_133(mode=4) | TFP410 (6) |
| 10 | DVI_PUP | - | Control signal for DVI controler (Expansion) | - | TFP410 (6)
|
| 11 | DVI_PCLK | DSS_PCLK | LCD clock (Expansion) |
GPIO_66 (mode=4) |
TFP410 (6)
|
| 12 | TS_nPEN_IRQ | McSPI1_CS1 | Touchscreen control (Expansion) |
MMC3_CMD(mode=3) GPIO_175 (mode=4) |
- |
| 13 | LCD_QVGA/nVGA | McBSP4_DX | Touchscreen control (Expansion) |
GPIO_154 (mode=4) |
-
|
| 14 | LCD_ENVDD | McBSP4_DR | Touchscreen control (Expansion) |
GPIO_153 (mode=4) |
- |
| 15 | LCD_RESB | McBSP4_FSX | Touchscreen control (Expansion) |
GPIO_155 (mode=4) |
- |
| 16 | LCD_INI | McBSP4_CLKX | Touchscreen control (Expansion) |
GPIO_152 (mode=4) |
-
|
| 17 | MCSPI1_CLK |
McSPI1_CLK |
Touchscreen control (Expansion) |
GPIO_171 (mode=4) |
- |
| 18 | MCSPI1_SIMO | McSPI1_SIMO | Touchscreen control (Expansion) |
GPIO_172 (mode=4) |
- |
| 19 | MCSPI1_CS0 | McSPI1_CS0 | Touchscreen control (Expansion) |
GPIO_174 (mode=4) |
- |
| 20 | MCSPI1_SOMI | McSPI1_SOMI | Touchscreen control (Expansion) |
GPIO_173 (mode=4) |
- |
(6): TFP410: Converts DVI signal to HDMI. They share the same video signal.
JA41 connector
JA41 is used for DVI (Digital Video Interface) data part.
-There are some peripherals than can be connected to JA41 like DSSVENC, HW, DSS and SDI, but is not used in this how-to.
Some pads have mux capabilities:
| Pad: | Connect to: |
Default peripheral (mode=0) |
Default function: | Other available peripherals: | Share with: |
| 1 | VIO 3V3 | - | Power 3v3 | - | - |
| 2 | GND |
- |
GND |
- |
- |
| 3 | DVI_DATA0 | DSS_D0 | LCD pixel data bit |
UART1_CTS(mode=2) GPIO_70(mode=4) |
TFP410 (6) |
| 4 | DVI_DATA1 | DSS_D1 | LCD pixel data bit |
UART1_RTS(mode=2) GPIO_71(mode=4) |
TFP410 (6)
|
| 5 | DVI_DATA2 |
DSS_D2 |
LCD pixel data bit |
GPIO_72(mode=4) |
TFP410 (6) |
| 6 | DVI_DATA3 |
DSS_D3 |
LCD pixel data bit |
GPIO_73(mode=4) |
TFP410 (6) |
| 7 | DVI_DATA4 | DSS_D4 | LCD pixel data bit |
UART3_RX(mode=2) GPIO_74(mode=4) |
TFP410 (6) |
| 8 | DVI_DATA5 | DSS_D5 | LCD pixel data bit |
UART3_TX(mode=2) GPIO_75(mode=4) |
TFP410 (6) |
| 9 | DVI_DATA6 | DSS_D6 | LCD pixel data bit |
UART1_TX(mode=2) GPIO_76(mode=4) |
TFP410 (6) |
| 10 | DVI_DATA7 | DSS_D7 | LCD pixel data bit |
UART1_RX(mode=2) GPIO_77(mode=4) |
TFP410 (6)
|
| 11 | DVI_DATA8 | DSS_D8 | LCD pixel data bit |
GPIO_78(mode=4) |
TFP410 (6)
|
| 12 | DVI_DATA9 | DSS_D9 | LCD pixel data bit |
GPIO_79(mode=4) |
TFP410 (6) |
| 13 | DVI_DATA10 | DSS_D10 | LCD pixel data bit |
GPIO_80(mode=4) |
TFP410 (6)
|
| 14 | DVI_DATA11 | DSS_D11 | LCD pixel data bit |
GPIO_81(mode=4) |
TFP410 (6) |
| 15 | DVI_DATA12 | DSS_D12 | LCD pixel data bit |
GPIO_82(mode=4) |
TFP410 (6) |
| 16 | DVI_DATA13 | DSS_D13 | LCD pixel data bit |
GPIO_83(mode=4) |
TFP410 (6)
|
| 17 | DVI_DATA14 |
DSS_D14 |
LCD pixel data bit |
GPIO_84(mode=4) |
TFP410 (6) |
| 18 | DVI_DATA15 | DSS_D15 | LCD pixel data bit |
GPIO_85(mode=4) |
TFP410 (6) |
| 19 | DVI_DATA16 | DSS_D16 | LCD pixel data bit |
GPIO_86(mode=4) |
TFP410 (6) |
| 20 | DVI_DATA17 | DSS_D17 | LCD pixel data bit |
GPIO_87(mode=4) |
TFP410 (6) |
| 21 |
DVI_DATA18 | DSS_D18 | LCD pixel data bit |
DSS_D0 (mode=3) MCSPI3_CLK(mode=2) GPIO_88(mode=4) |
TFP410 (6) |
| 22 |
DVI_DATA19 | DSS_D19 | LCD pixel data bit |
DSS_1 (mode=3) MCSPI3_SIMO(mode=2) GPIO_89(mode=4) |
TFP410 (6) |
| 23 |
DVI_DATA20 | DSS_D20 | LCD pixel data bit |
DSS_D2 (mode=3) MCSPI3_SOMI(mode=2) GPIO_90(mode=4) |
TFP410 (6) |
| 24 |
DVI_DATA21 | DSS_D21 | LCD pixel data bit |
DSS_3 (mode=3) MCSPI3_CSO(mode=2) GPIO_91(mode=4) |
TFP410 (6) |
| 25 |
DVI_DATA22 |
DSS_D22 |
LCD pixel data bit |
DSS_D4 (mode=3) MCSPI3_CS1(mode=2) GPIO_92(mode=4) |
TFP410 (6) |
| 26 |
DVI_DATA23 |
DSS_D23 |
LCD pixel data bit |
DSS_D5(mode=3) GPIO_93(mode=4) |
TFP410 (6) |
| 27 |
I2C3_SCL |
I2C3_SCL | I2C3 interface |
GPIO_184(mode=4) |
TXS0102DCUR |
| 28 |
I2C3_SDA |
I2C3_SDA | I2C3 interface |
GPIO_185(mode=4) |
TXS0102DCUR |
(6): TFP410: Converts DVI signal to HDMI. They share the same video signal.
Under construction
