How do I get a /IOWR Pulse for accessing external IO devices?
I am using a RCM3000 core and dropped back to the prototyping board to minimize the system.
I have tried WrPortE(0x33,&c,IntData);
I have tried the assembler version ioe ld(0x33),a
I have tried #define PortA_AUX_IO
I do not get the /IOWR pulse but the address on the external IO bus changes when the instruction executes.
When I do a RdPortE(0x33); I get a /IORD pulse as expected.
Any Ideas on what I am doing wrong or have forgotten to do?
Thanks, David
The define of PortA_AUX_IO only enables the aux I/O port, it does not setup an external I/O bank, which is needed if you want to write to the port. External I/O banks are defined by the group of IBxCR registers. Each IBxCR register has a bit which enables writing within that bank. See section 10 of the Rabbit 3000 Microprocessor User�s Manual for more details on external I/O ports, the IBxCR registers and their related address ranges.