Memory Maps

 

 

 

 

 

Table 1-12. Z85230 SCC Register Addresses

 

 

 

 

 

SCC

Z85230 SCC Register

Address

 

 

 

 

 

SCC #1

Port B Control

$FFF45001

 

(All MVME172

 

 

 

Port B Data

$FFF45003

 

modules)

 

 

 

 

Port A Control

$FFF45005

 

 

 

 

 

 

 

 

Port A Data

$FFF45007

 

 

 

 

 

SCC #2

Port B Control

$FFF45801

 

(200/300-Series

 

 

 

Port B Data

$FFF45803

 

MVME172

 

 

 

 

Port A Control

$FFF45805

 

only)

 

 

Port A Data

$FFF45807

 

 

 

 

Note A bug in MVME172s that have MC2 chip revision $01 does not allow the data registers to be accessed directly. You must access them indirectly via the SCC chip. The software must send a command to the control register that tells it that the next thing read or written to the control register will go to the data register. The following two macros are examples:

dev_addr is a pointer to the base address of the SCC. SCCR0 is the offset to the SCC control register #0.

#define READ_SCC(VAR_NAME)\ dev_addr[SCCR0] = 0x08;\ (VAR_NAME) = dev_addr[SCCR0]

#define WRITE_SCC(VAR_NAME)\ dev_addr[SCCR0] = 0x08;\ dev_addr[SCCR0] = (VAR_NAME)

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Motorola MVME172 manual 12. Z85230 SCC Register Addresses