
Chapter 2: 4538
The instruction and data caches are enabled through bits ICE and DCE of register HID0 respectively. The setting of ICE bit must be preceded by an isync instruction. The setting of DCE bit must be preceded by a sync instruction.
Communication Processor Module Initialization
I/O Port Initialization
The CPM I/O ports have to be configured according to their usage (see Communication Processor Module (CPM) I/O Ports on page 8). In the Interphase boot firmware, this is done during the early phase of the boot (in startup.asm).
Each CPM port is set by four registers in the Internal Register Area: PDIRx, PPARx, PODRx, and PDATx.
Table 2-3. CPM Port Register initialization Values
Register | Address | Init. Value | Comment |
|
| ||
33$5$ [))' [ |
| ||
|
|
|
|
3625$ | [))' | [ |
|
|
|
|
|
3'$7$ | [))' | [ | 6:02'(B1 &20&/.B1 |
|
|
|
|
3',5$ | [))' | [)'))))) |
|
|
| ||
|
| ||
33$5% [))' [ |
| ||
|
|
|
|
3625% | [))' | [ |
|
|
| ||
3'$7% [))' [ |
| ||
|
|
|
|
3',5% | [))' | [ |
|
|
| ||
|
| ||
33$5& [))' [ |
| ||
|
|
|
|
3625& | [))' | [ |
|
3'$7& [))' [ 4XDG)DOF(WKHUQHWUHVHWGHDFWLYDWHG
3',5& [))' [)))))&$
33$5' [))' [
3625' [))' [
3'$7' [))' [ /('VRII
3',5' [))' [))
CPM RCCR Reset
At boot, it is important to reset the RISC Controller Configuration Register (RCCR) in order to disable any previously loaded CPM microcode and start with the known default CPM microcode.
4538 Hardware Reference Manual | 67 |