TMS570LS0432 SPI + 23LC1024SRAM

pavithra pavithra

Intellectual 870 points

Other Parts Discussed in Thread: HALCOGEN

Hi ti,

i m trying to write and read a byte to external SRAM using spi.

5635.spi.zip

i ve written a code. spi is configured as master. the setting are default in halcogen.

i am getting 1MHz clock as configured. but i cannot transmit and receive data.

can anyone pls help me to find what is wrong and how to change that.

any example code regarding this is appreciated.

thanks in advance

over 9 years ago

0 pavithra pavithra over 9 years ago

Intellectual 870 points

i ve a strange problem.

when i see in scope i get output. i checked in slave out pin of 23lc1024.... i get the waveform.. i compared the master output and slave output, there is difference only in the amplitude.... but i dint receive any data in RxBUF..... what will be problem?

and in my another post i ve asked regarding the jumper settings J8 and J9 in launchpad. do they have anything to do with this?

please anyone explain me.

1602.spi_new.zip

0 Zhaohong Zhang over 9 years ago in reply to pavithra pavithra

TI__Mastermind 22715 points

Hi, there.

The datasheet of 23lc1024 requires that the CS pin stays low during the entire period of read or write. It also uses 8 bit data size. You cannot use the Halcogen functions as is. You need to write your own function. You can use the halcogen function as the base.

Thanks and regards,

Zhaohong

0 pavithra pavithra over 9 years ago in reply to Zhaohong Zhang

Intellectual 870 points

Hi ZHANG,

as u said i wrote new functions using the registers.
i've some doubt regarding chip select.

1. i compared the timing diagram of spi and sram and concluded that clock polarity=0 and clock phase=1.
2. i m using DAT1 reg for data txn.
in DAT1 reg CSNR field describes the chip select to be active during txn.

0 pavithra pavithra over 9 years ago in reply to pavithra pavithra

Intellectual 870 points

i m using chip select 1. hence CSNR = 0xFD

0 pavithra pavithra over 9 years ago in reply to pavithra pavithra

Intellectual 870 points

What is the purpose of SPIDEF register? for writing data in SRAM i ve make chip select low. should i use CSNR field or SPIDEF reg for this?
what is the use of CSHOLD bit? when should be used?

and i m always reading 0xFF in SOMI pin.... what will be the cause for this?
anyone please clarify these doubts.