Siemens ERTEC200

4.2 General Purpose I/O (GPIO)

Up to 45 General Purpose Inputs/Outputs are available in the ERTEC 200. These are divided into two groups:

• GPIO[31:0] 32 bits on the APB I/O bus

• GPIO[44:32] 13 bits as an alternative function on the LBU interface

The GPIOs [31 : 0] can be used as follows

• Inputs

• Outputs

• One of up to 3 additional special functions (Watchdog, Timer, F-Timer, UART, SPI, ETM and MC-PLL)

The direction of the IO can be programmed bit-by-bit in the "GPIO_IOCTRL“ register.

The function selection of the special I/O functions can be programmed in the GPIO_PORT_MODE_L and

GPIO_PORT_MODE_H registers.

The GPIO inputs [1 : 0] and [31 : 30] can also be used as external interrupt inputs. They are connected at the IRQ

interrupt controller of the ARM946. The polarity of the GPIO interrupts can be specified with the GPIO_POLSEL register

(see GPIO register description)

The following figure shows the structure of a GPIO[31 : 0] pin as a normal I/O function or as an alternative function.

GPIO(i)

GPIO

OUT (i)

Alternate function 1,2,3 (if input)

Alternate function 1,2,3 (if output)

GPIO

IOCTRL(i)

GPIO_PORT

MODE_L&..._H

(2*i+1, 2*i)

Pin of

ERTEC200

Figure 4: GPIO Cell on GPIO Port [31:0] of the ERTEC 200

The GPIOs [44 : 32] are available on the LBU bus when the LBU interface is not used. The selection is made with the

configuration pin CONFIG[2] = 1. The GPIOs[44:32] can then be used as normal inputs or outputs. The direction of the

GPIOs[44:32] can be programmed bit-by-bit in the "GPIO_IOCTRL2“ register.

Technical data subject to change Version 1.1.0