EVM5505 how many SPI devices can be used?

Peter16037

Hello,

I use Spectrum Digital EVM for C5505. I connected a DAC on the connector J22 to the SPI port and the DAC working.

In the manual for the EVM I saw expansions connector J5. There are two SPI_CS0 and SPI_ALT_CS1, SPI_ALT_CS2, SPI_ALT_CS3. Is the SPI_CS and SPI_ALT_CS the same?

Can I connect more than one SPI slave device on the EVM board?

Thanks,

Peter

over 15 years ago

0 Mark M over 15 years ago

TI__Mastermind 30140 points

Hi Peter,

The C5505 DSP has 4 external SPI Chip Select signals and can support up to 4 SPI slave devices. The C5505 EVM has SPI_CS0, SPI_CLK, SPI_DX, and SPI_RX wired to the J22 header.

The signals present on the J5 header are multiplexed to accommodate a larger number of peripheral functions in the smallest possible package. The external bus selection register (EBSR) determines the mapping of the LCD controller, I2S2, I2S3, UART, SPI, and GPIO signals to 21 signals of the external parallel port pins. (See 4.7 Multiplexed Pin Configurations in the C5505 Datasheet and 7.3 Device Configuration in the C5505 DSP System User's Guide)

To map the SPI_CS1, SPI_CS2, or SPI_CS3 signals to header J5, you need to set the Parallel port mode bits (PPMODE) of the EBSR to either Mode 1 or Mode 6.

With the EBSR PPMODE is in Mode 1 or Mode 6, the SPI signals will map to Header J5 as follows:

Signal	Header	EVM Signal Name
SPI_CLK	J5, Pin 41	LCD_RE / SPI_ALT_CLK
SPI_RX	J5, Pin 40	LCD_DATA0 / SPI_ALT_RX
SPI_TX	J5, Pin 38	LCD_DATA1 / SPI_ALT_DX
SPI_CS0	J5, Pin 37	LCD_BIAS_OE / SPI_CS0
SPI_CS1	J5, Pin 36	LCD_MCLK / SPI_ALT_CS1
SPI_CS2	J5, Pin 35	LCD_nWE / SPI_ALT_CS2
SPI_CS3	J5, Pin 34	LCD_ALE / SPI_ALT_CS3

Note that after changing any of the pin mux control registers, it will be necessary to reset the peripherals that are affected.

Hope this helps,

Mark

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EVM5505 how many SPI devices can be used?