Interphase Tech 4538 - Manual (Page 89)

Chapter 2: 4538 Power-Up Initialization
4538 Hardware Reference Manual 67
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.
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.
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'$7& [))' [ 4XDG)DOF (WKHUQHW UHVHW GHDFWLYDWHG
3',5& [))' [)))))&$
33$5' [))' [
3625' [))' [
3'$7' [))' [ /('V RII
3',5' [))' [))