November 11, 2020

Maple and Maple-mini pins

For those (like me) using some form of libmaple, it is important to understand the maple pin numbering scheme. The Maple software assigned sequential numbers to the pins, D0 to D33 for the maple-mini and D0-D42 for the maple. These two number schemes do not correspond in any way. In other words, D1 on the mini is not the same GPIO port as D1 on the maple. You are supposed to "not care" and in general you don't if you are just manipulating a single GPIO pin. What the numbers do correspond to is the silkscreen labeling on the boards which is sensible and sequential. If you are looking for some alternate function pin like TX_3, it is D29 on the maple and D1 on the mini.

The pins on the blue pill are something else entirely. There is no handy sequential "D" numbering on the silkscreen and the board is not laid out in the same way as the maple-mini.

What you are probably itching for now are some diagrams and tables, so here we go.

Here is the maple-mini pinout. Note that somebody got the idea of giving software names to the pins as shown whith white text on a blue background (such as "PC_13"). This would have the advantage of the same name for a given GPIO pin regardless of what connector pin it was routed to on the board. Both this and the name "D14" for the same pin would have their own advantages.

Here is the blue pill pinout. Note that we now have a handy SWD connector on the end. Also note that there is virtually no correspondence to signal locations on the maple-mini and no handy sequential "D" numbering on the silkscreen.

The Maple board is an entirely different beast. Perhaps because it is much rarer in the wild, I haven't found an equivalent handy diagram like the above. You have to go with the silkscreen "D" number markings and the following tables (from the original Leaf Labs documents).

Here is the "master pin map" for the Maple mini:

Pin GPIO ADC Timer I2C UART SPI 5 V?
D0 PB11
2_SDA 3_RX
Yes
D1 PB10
2_SCL 3_TX
Yes
D2 PB2
Yes
D3 PB0 CH8 3_CH3
D4 PA7 CH7 3_CH2
1_MOSI
D5 PA6 CH6 3_CH1
1_MISO
D6 PA5 CH5
1_SCK
D7 PA4 CH4
2_CK 1_NSS
D8 PA3 CH3 2_CH4
2_RX
D9 PA2 CH2 2_CH3
2_TX
D10 PA1 CH1 2_CH2
2_RTS
D11 PA0 CH0 2_CH1_ETR
2_CTS
D12 PC15
D13 PC14
D14 PC13
D15 PB7
4_CH2 1_SDA
Yes
D16 PB6
4_CH1 2_SCL
Yes
D17 PB5
1_SMBA
D18 PB4
Yes
D19 PB3
Yes
D20 PA15
Yes
D21 PA14
Yes
D22 PA13
Yes
D23 PA12
1_ETR
1_RTS
Yes
D24 PA11
1_CH4
1_CTS
Yes
D25 PA10
1_CH3
1_RX
Yes
D26 PA9
1_CH2
1_TX
Yes
D27 PA8
1_CH1
1_CK
Yes
D28 PB15
2_MOSI Yes
D29 PB14
3_RTS 2_MISO Yes
D30 PB13
3_CTS 2_SCK Yes
D31 PB12
1_BKIN 2_SMBA 3_CK 2_NSS Yes
D32 PB8
4_CH3
Yes
D33 PB1 CH9 3_CH4

And here is the "master pin map" for the Maple:

Pin GPIO ADC Timer I2C UART SPI 5 V?
D0 PA3 CH3 2_CH4
2_RX
D1 PA2 CH2 2_CH3
2_TX
D2 PA0 CH0 2_CH1_ETR
2_CTS
D3 PA1 CH1 2_CH2
2_RTS
D4 PB5
1_SMBA
D5 PB6
4_CH1 1_SCL
Yes
D6 PA8
1_CH1
1_CK
Yes
D7 PA9
1_CH2
1_TX
Yes
D8 PA10
1_CH3
1_RX
Yes
D9 PB7
4_CH2 1_SDA
Yes
D10 PA4 CH4
2_CK 1_NSS
D11 PA7 CH7 3_CH2
1_MOSI
D12 PA6 CH6 3_CH1
1_MISO
D13 PA5 CH5
1_SCK
D14 PB8
4_CH3
Yes
D15 PC0 CH10
D16 PC1 CH11
D17 PC2 CH12
D18 PC3 CH13
D19 PC4 CH14
D20 PC5 CH15
D21 PC13
D22 PC14
D23 PC15
D24 PB9
4_CH4
Yes
D25 PD2
3_ETR
Yes
D26 PC10
Yes
D27 PB0 CH8 3_CH3
D28 PB1 CH9 3_CH4
D29 PB10
2_SCL 3_TX
Yes
D30 PB11
2_SDA 3_RX
Yes
D31 PB12
2_SMBA 3_CK 2_NSS Yes
D32 PB13
3_CTS 2_SCK Yes
D33 PB14
3_RTS 2_MISO Yes
D34 PB15
2_MOSI Yes
D35 PC6
Yes
D36 PC7
Yes
D37 PC8
Yes
D38 PC9
Yes
D39 PA13
Yes
D40 PA14
Yes
D41 PA15
Yes
D42 PB3
Yes

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Tom's Computer Info / tom@mmto.org