Pmod接口标准是由Xilinx的第三方合作伙伴迪芝伦（Digilent）制定的接口扩展规范，除了我们经常看到的FMC扩展接口，Pmod接口应用也越来越广泛，由于FPGA I/O接口的灵活性，Pmod接口非常适合FPGA开发板卡与外设实现连接。此外迪芝伦（Digilent）为了解决与特定微控制器接口的连接推出了不同引脚排列的类型。
1、连接器标准
Pmod接口分为HOST和和Peripheral两种类型，分为6pin、8pin和12pin等几类，详见“Digilent Pmod interface Specification Revision:November 20, 2011”。
2、I/O信号定义
针对不同应用，不用接口类型，其连接器的信号定义不同，详见下表：
接口类型 | Pin Num | Signal | Direction |
I2C Interface | 1/2 | SCL | |
3/4 | SDA | ||
5/6 | GND | ||
7/8 | VCC | ||
Pmod Interface Type 1 (GPIO) | 1 | IO1 | In/Out |
2 | IO2 | In/Out | |
3 | IO3 | In/Out | |
4 | IO4 | In/Out | |
5 | GND | ||
6 | VCC | ||
Pmod Interface Type 2 (SPI) | 1 | SS | Out |
2 | MOSI | Out | |
3 | MISO | In | |
4 | SCK | Out | |
5 | GND | ||
6 | VCC | ||
Pmod Interface Type 2A (expanded SPI) | 1 | SS | Out |
2 | MOSI | Out | |
3 | MISO | In | |
4 | SCK | Out | |
5 | GND | ||
6 | VCC | ||
7 | INT | In | |
8 | RESET | Out | |
9 | N/S | not-specified | |
10 | N/S | not-specified | |
11 | GND | ||
12 | VCC | ||
Pmod Interface Type 3 (UART) | 1 | CTS | Out |
2 | RTS | In | |
3 | RXD | In | |
4 | TXD | Out | |
5 | GND | ||
6 | VCC | ||
Pmod Interface Type 4 (UART) | 1 | CTS | In |
2 | TXD | Out | |
3 | RXD | In | |
4 | RTS | Out | |
5 | GND | ||
6 | VCC | ||
Pmod Interface Type 4A (expanded UART) | 1 | CTS | In |
2 | TXD | Out | |
3 | RXD | In | |
4 | RTS | Out | |
5 | GND | ||
6 | VCC | ||
7 | INT | In | |
8 | RESET | Out | |
9 | N/S | ||
10 | N/S | ||
11 | GND | ||
12 | VCC | ||
Pmod Interface Type 5 (H-Bridge) | 1 | DIR | Out |
2 | EN | Out | |
3 | SA | In | |
4 | SB | In | |
5 | GND | ||
6 | VCC | ||
Pmod Interface Type 6 (dual H-Bridge) | 1 | DIR1 | Out |
2 | EN1 | Out | |
3 | DIR2 | Out | |
4 | EN2 | Out | |
5 | GND | ||
6 | VCC |
注：‘Out’means from the host to the peripheral; ‘In’ means from the peripheral to thehost. 详细信息参见接口标准：“Digilent Pmod interface Specification Revision:November 20, 2011”。
