Peripheral Control Module

11.3Interrupts

Each peripheral unit interfaces to the interrupt controller within the system control module. The interrupt controller contains a 32-bit interrupt pending register, which when read, informs the user of all the units on the SA-1100 that are currently generating an unmasked interrupt. Once the user determines which unit is causing the interrupt, the unit’s status registers can be read to determine the exact cause of the interrupt. This mechanism provides a two-level approach to identify the source of any interrupt from the hundreds of possible interrupt sources that exist on the SA-1100.

Each of the peripheral units generate either one or two interrupts that correspond to specific interrupt pending bits within the interrupt controller. Serial ports 1 and 4 each contain two independent serial engines. Although each peripheral uses only one set of pins for serial communication, the user may choose to use both serial engines within serial ports 1 and 4 by assigning one of the two protocols to communicate off-chip by taking control of GPIO pins. Because the two engines within serial ports 1 and 4 can operate at the same time, these two units are assigned two separate interrupt request numbers within the interrupt controller’s pending register. Table 11-3shows the interrupt level for each of the peripheral control units.

Table 11-3. Peripheral Units’ Interrupt Numbers

 

 

Interrupt

Peripheral

Number

 

 

LCD controller

12

 

 

Serial port 0: USB

13

 

 

 

Serial port 1:

SDLC

14

 

 

UART

15

 

 

 

 

Serial port 2: ICP

16

 

 

Serial port 3: UART

17

 

 

 

Serial port 4:

MCP

18

 

 

SSP

19

 

 

 

 

11-4

SA-1100 Developer’s Manual

Page 154
Image 154
Intel SA-1100 manual Interrupts, Peripheral Units’ Interrupt Numbers