AN413 datasheet(7/45 Pages) STMICROELECTRONICS

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AN413

ST9 basic system configuration

Doc ID 1875 Rev 2

7/45

.word ADC_EOC

ADC_WDG:

; Code for the Analog Watchdog Routine is included here

; Note that in the example in Appendix B

; the System Reset routine is invoked for out of

; range conditions on Channels 6 and 7

iret

ADC_EOC:

; End of A/D conversion interrupt routine included here

iret

3.2

Port initialization

The ST9 has up to a maximum of 64 lines dedicated to input/output. These lines, grouped

into eight 8-bit ports, can be independently programmed to provide parallel input/outputs

with or without handshake or may be used to connect in/out signals to/from the peripherals

(e.g. Core, Timers, SCI units, etc.) present on the chip. The functional allocation of the Ports

to support system tasks may be summarized as follows:

Ports 0, 1, and 6 are automatically initialized on system Reset to correspond to the installed

on-chip memory.

Ports 2, 3, 4, 5, 6, and 7 need to be initialized (if available) to satisfy the specific application

requirements

Table 2.

Port functional allocations

Port

Functions

Usable as I/O Port (without handshake) or as multiplexed low-address and data

lines for external memory.

Usable as I/O Port (without handshake) or as high-address lines for external

memory.

Usable as I/O Port (without handshake) or for SPI functions; Also INT1, INT2, and

INT3 inputs.

Usable as I/O Port (without handshake) or for Timer functions.

Usable as I/O Port (with or without handshake)

Usable as I/O Port (with or without handshake).

Usable as I/O Port (without handshake)

Usable as I/O Port (without handshake) or for SCI functions. Also used for INT4,

INT5, and INT6 inputs or for Control signals for slow external memory

AN413 Datasheet(PDF) 7 Page - STMicroelectronics