Re: [avr-gcc-list] MEGA128 with external SPI flash vs pointer

[opentv]

Użytkownik Wielebny napisał:
>Hello,
>I have external flash AT45B011 (SPI, 1Mbit)
>i need read & write this flash via pointer like internal eeprom.

Helo,

 

Dataflash can't be addressed like a standard memory. How do u want to do
this ??? As far as I know it's not possible to define an ordinary pointer to
a memory whitch is connected to the cpu by a serial interface.

I would suggest to treate dataflash like a file. It's possible to define a
fast filepointer (lseek) and functions like  "write" and "read". Atmega128
Spi Transmit (SPDR) register is double-buffered so you can use this
advantage to greatly speed-up transmission while reading (ask for the byte
nr N while reading the byte N-1). I obtained 720 kbytes/s in continous
read-mode and 28 kbytes/s in continous write mode (write to the buffer N
while burning data from the second one) on 8 MHz Atmega128L overclocked to
16 MHz (5V) and 16 Mbits AT dataflash (SPI: 8 MHz).

 

Good lack,

 

Krzysztof from Poland.