Re: NCR 7452/3 POS - Retail CMOS NVRAM Driver

[Gabriel Gomiz <gomita@bblanca.com.ar>]

Richard B. Johnson wrote:
> On Wed, 15 Jan 2003, Gabriel Gomiz wrote:
>>
>>The memory chips that NCR uses are:
>>1) NEC D43256BGU - NCR POS Model 7452-1011
>>    The chip is 256KB, but NCR says they use only 128KB
>>2) NEC D431000AGW - NCR POS Model 7453-1011
>>    The chip is 1MB, but NCR says they use only 128KB
>>
> 
> Look in the ethernet drivers for the "bit-banging" routines
> used to access NVRAM in the devices. You need to shift bits
> in and out of these devices. They are SERIAL ERPROMS. You
> can get data sheets by using your favorite search engine
> (as I just did).

I grabbed the datasheets of the memory chips and found out the 
following, that changes the incorrect information that I had:

1) NEC D43256BGU is 256Kbits = 32KB (32768 words of 8 bits)

This chip has 15 address lines (A0-A14) and 8 data lines (I/O1 - I/O8).

2) NEC D431000AGW is 1Mbit = 128KB (131072 word of 8 bits)

This chip has 17 address lines (A0-A16) and 8 data lines (I/O1 - I/O8).

So it seems that these chips doesn't have a serial-like interface for 
bit-banging, I am wrong?

-- 
    .^.    Gabriel Gomiz - Red Hat Certified Engineer (RHCE)
    /V\
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