Duovero Multiplexes

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This wiki entry concentrates on the Duovero Parlor board and the Multiplexes available from the 40 pin connector.

Duovero parlor conn small.png

The ground pin is nearest the console connector port and the power pins are nearest the centre of the board. This is as of writing but it is highly recommended that you check before connecting! Use a voltmeter to check the 3.3V, 5V and 1.8V pins to familiarise yourself with the layout.

There are also two connections on the Parlor board:

OMAP Pin GPIO # Purpose
AG24 GPIO121 user push button
AH24 GPIO122 user LED

You should start your journey here.

The primary reference for multiplexes and pin functions is the Texas Instruments OMAP4 technical reference manual. The short version of that 6000 page manual is the OMAP4430 datasheet which is easier to search. The primary source reference is in the Uboot code, specifically duovero_mux_data.h which uses the defines from ./arch/arm/include/asm/arch-omap4/mux_omap4.h.


Software Muxing

A helpful post from Phil Lutz describes how multiplexing can be explored without kernel recompilation. The default multiplex for the user LED may not be set to GPIO in Uboot. It certainly is not set to GPIO by the OMAP itself. You can look at the OMAP datasheet on page 48 you can see that the official name for GPIO 122 pin is "abe_dmic_din3" (Mode 0 names are accepted pin names).

This information can also be found by searching for "gpio_122" in the board pinmuxing configuration stored in sysfs: /sys/kernel/debug/omap_mux/board/core. Every pin which can be configured as gpio has a hint about that.

So now just check which is the current pinmuxing configuration for this pin by:

$ cat /sys/kernel/debug/omap_mux/abe_dmic_din3 
name: abe_dmic_din3.abe_dmic_din3 (0x4a100116/0x116 = 0x0100), b ah24, t NA
mode: OMAP_PIN_INPUT | OMAP_MUX_MODE0
signals: abe_dmic_din3 | slimbus2_data | abe_dmic_clk2 | gpio_122 | NA | dmtimer9_pwm_evt | NA | safe_mode

As the output suggests, the pin is configured in MODE0, this is 'abe_dmic_din3'. The other modes are listed in order as they appear in the OMAP data manual. gpio_122 is multiplex MODE 3. You can set it with:

 $ echo 3 > /sys/kernel/debug/omap_mux/abe_dmic_din3

Now you can turn on and off the LED using the usual gpio configuration in /sys/class/gpio/ (google it!). Note that "echo 3" does more than set Mode 3. The number is a selection of bits that set various states for the pin. A quick summary is:

Bit 0,1,2 Set the mode
Bit 3 0 = pull up/down disabled , 1 = enabled
Bit 4 0 = pull down, 1 = pull up
Bit 8 0 = Output only. 1 = input enable (bidirectional)

There are more but these are for sleep modes and wakeup. The manual has details. The defines in mux_omap4.h are useful for interpreting the duovero_mux_data.h file:

IEN 1 << 8 Input enable (bidirectional)
IDIS 0 << 8 Output only
PTU   3 << 3   Enable Pullup
PTD 1 << 3 Enable Pulldown
EN 1 << 3 PU/PD enable
DIS 0 << 3 PU/PD disable

Parlor pin mux table

To assist in figuring out which pins on the Parlor board can be assigned to which duties, here's a table of functions. Mode 7 is "safe_mode" where the pin is effectively disconnected from any functionality. It's set to high impedance (Z) and is left out of the table. The bolded functions are those set by the current U-Boot duovero_mux_data.h. This file sets other parameters (eg: output only, disable pullup/pulldown, etc) and you must refer to the U-Boot file to know what the full state is. A partial indication of the state (wake mode) is indicated in the table by arrows (bidirectional, output, pullup, pulldown).

Underneath the Connector entries are the IOPAD mux address offsets and under each gpio entry is the corresponding GPIO register and bit offset. These numbers are useful for device tree purposes. The gpio numbers are calculated simply as: register = int(gpionumber / 32) + 1 and offset = gpionumber % 32.


Connector Description OMAP Pin Reset state Mode 0 Mode 1 Mode 2 Mode 3 Mode 4 Mode 5 Mode 6
User LEDa
0x116
AH24 M7, Pulldown   abe_dmic_din3 slimbus2_data abe_dmic_clk2 gpio_122
GPIO4[26]
- dmtimer9_pwm_evt -
Buttona
0x114
AG24 M7, Pulldown abe_dmic_din2 slimbus2_clock abe_mcasp_axr gpio_121
GPIO4[25]
- dmtimer11_pwm_evt -
04: MCSPI1_CS0
0x138
AE23 M7, Pulldown mcspi1_cs0 ⇔↓ - - gpio_137
GPIO5[9]
- - -
06: MCSPI1_CS1
0x13A
AF23 M7, Pulldown mcspi1_cs1 ⇔↓ uart1_rx - gpio_138
GPIO5[10]
- - -
08: MCSPI1_CS2
0x13C
AG23 M7, Pullup mcspi1_cs2 uart1_cts slimbus2_clock gpio_139
GPIO5[11]
- - -
10: MCSPI1_CS3
0x13E
AH23 M7, Pullup mcspi1_cs3 uart1_rts slimbus2_data gpio_140
GPIO5[12]
- - -
03: MCSPI1_CLK
0x132
AF22 M7, Pulldown mcspi1_clk - - gpio_134
GPIO5[6]
- - -
05: MCSPI1_SIMO
0x136
AG22 M7, Pulldown mcspi1_simo - - gpio_136
GPIO5[8]
- - -
07: MCSPI1_SOMI
0x134
AE22 M7, Pulldown mcspi1_somi - - gpio_135
GPIO5[7]
- - -
09: HDQ_SIOb
0x120
AA27 M7, Z hdq_sio i2c3_sccb i2c2_sccb gpio_127
GPIO4[31]
- - -
12: I2C2_SCLc
0x126
C26 M7, Pullup i2c2_scl ⇔↑ uart1_rx - gpio_128
GPIO5[0]
- - -
14: I2C2_SDAc
0x128
D26 M7, Pullup i2c2_sda ⇔↑ uart1_tx - gpio_129
GPIO5[1]
- - -
11: SDMMC3_CMD
0x174
AG10 M7, Pullup usbb2_ulpitll_dat6 usbb2_ulpiphy_dat6 sdmmc3_cmd gpio_167 ⇔↑
GPIO6[7]
mcspi3_simo dispc2_data12 rfbi_data12
13: SDMMC3_CLK
0x176
AE9 M7, Pullup usbb2_ulpitll_dat7 usbb2_ulpiphy_dat7 sdmmc3_clk gpio_168 ⇔↑
GPIO6[8]
mcspi3_clk dispc2_data11 rfbi_data11
15: UART2_TX
0x11E
AA26 M7, Pullup uart2_tx sdmmc3_dat1 - gpio_126
GPIO4[30]
- - -
17: UART2_RX
0x11C
AA25 M7, Pullup uart2_rx ⇔↑ sdmmc3_dat0 - gpio_125
GPIO4[29]
- - -
19: BSP2_CLKX
0x0F6
AD27 M7, Pulldown abe_mcbsp2_clkx mcspi2_clk abe_mcasp_ahclkx gpio_110
GPIO4[14]
usbb2_mm_rxdm - -
20: BSP2_FSX
0x0FC
AC28 M7, Pulldown abe_mcbsp2_fsx mcspi2_cs0 abe_mcasp_afsx gpio_113
GPIO4[17]
usbb2_mm_txen - -
21: BSP2_DX
0x0FA
AD25 M7, Pulldown abe_mcbsp2_dx mcspi2_simo abe_mcasp_amute gpio_112
GPIO4[16]
usbb2_mm_rxrcv - -
22: BSP2_DR
0x0F8
AD26 M7, Pulldown abe_mcbsp2_dr mcspi2_somi abe_mcasp_axr gpio_111
GPIO4[15]
usbb2_mm_rxdp - -
23: BSP_CLKS
0x10E
AH26 M7, Pulldown abe_clks ⇔↓ - - gpio_118
GPIO4[22]
- - -
25: MCSPI4_SOMI
0x158
AF21 M7, Pullup mcspi4_somi sdmmc4_dat0 kpd_row6 gpio_153
GPIO5[25]
- - -
27: MCSPI4_SIMO
0x156
AF20 M7, Pullup mcspi4_simo sdmmc4_cmd kpd_col7 gpio_152
GPIO5[24]
- - -
29: MCSPI4_CLK
0x154
AE21 M7, Pulldown mcspi4_clk sdmmc4_clk kpd_col6 gpio_151
GPIO5[23]
- - -
31: MCSPI4_CS0
0x15A
AE20 M7, Pullup mcspi4_cs0 ⇔↓ sdmmc4_dat3 kpd_row7 gpio_154
GPIO5[26]
- - -

Notes

a) Assigned as such in u-boot but reassigned in the kernel board startup code to Mode 3 Outputs

b) There is a 10K pull up to 1.8V, internal to the DuoVero COM, on the HDQ_SIO line. Do not enable a pull down on this line. This will result in a non-logic output level (approximately 1V). This is currently considered to be a bug and may be removed in future COM revisions.

c) There are pullups on I2C2 and I2C3 of approximately 1K. S/C current is over 2mA.

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