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More chip selects

Hello all,

I have a CPU board which has a M16C/62P microcontroller and the microcontrollers three CS pins are connected to SRAM, EEPROM and ADC. Now I need to add LCD to the CPU board throuch the latch and I will need one more CS pin to the latch.

I am thinking to expand one of the microcontrollers CS pin to get two CS pins using address decoder in a way that this microcontrollers CS pin comes to the address decoder and based on address it selects one of the two CS pins.

Is there other possibilities mayby to expand CS pins?

Reply to
jtp
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Doesn't sound like a homework problem to me, so I'll take a stab:

Address decoding, the method that you describe, is the most common. And probably second most common would be indirect access, where you control which block or device gets the CS by way of writing to a control bit somewhere - for example: some sort of writable register on your data bus (which would need its own address decoding unless you have an unused data bit), or using a GPIO line, if one is available.

Marc

GPIO = general purpose I/O

Reply to
mrand

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