Using SPI mode to interface msp430 with RF transciever and SD card

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SUMMARY

The discussion focuses on interfacing the eZ430-RF2500, which includes a MSP430 microcontroller and a CC2500 RF transceiver, with a Sandisk Secure Digital Card using SPI mode. The MSP430 can act as the master while both the RF transceiver and the SD card serve as slaves. It is established that the STE pin can be utilized for chip selection, but caution is advised when sharing the same SPI lines, as improper configuration may lead to data conflicts. A NOT gate is recommended to ensure only one slave device is active at a time.

PREREQUISITES
  • Understanding of SPI communication protocols
  • Familiarity with MSP430 microcontroller architecture
  • Knowledge of RF transceiver operation, specifically the CC2500
  • Basic electronics concepts, including the use of NOT gates
NEXT STEPS
  • Research how to implement SPI communication with multiple slave devices
  • Learn about configuring the MSP430 for SPI master mode
  • Explore the use of NOT gates in digital circuit design
  • Investigate potential issues with SPI data conflicts and how to mitigate them
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Embedded systems developers, electronics engineers, and anyone working on projects involving MSP430 microcontrollers and SPI communication with multiple devices.

mz8e08
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Hi,

I am planning to use SPI mode to interface a eZ430-RF2500 with a Sandisk Secure Digital Card. The eZ430-RF2500 includes a MSP430 microcontroller and a CC2500 RF transceiver. According to the schematic, the RF transceiver interfaces the MSP430 utilizing the SPI mode, using the SOMI, SIMO, SCK, STE(for chip selecting) pins of MSP430.

The problem is can I connect the MSP430 with SD card using the same set of input wires(SOMI, SIMO, SCK, STE)? In this case, I suppose MSP430 is the master, both RF transceiver and SD card are slaves. If it is possible, how to use the STE signal to perform slave selecting. ALL the information I've got is that the chip selecting can be done by using the STE, but no detailed examples to demonstrate it.

Thanks
 
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You can do daisy chained SPI, although I don't think that is possible in this case.
I think you can use the STE pin to select between the SD and the CC2500. You have to use a not gate and make sure only one slave is selected at a time.
connect STE directly to chip select/slave select of cc2500. Use a not gate to connect STE to chip select pin of SD.
This is not recommended though coz whenever cc2500 is not selected, SD is selected. If you are not aware and send some clk pulses you might end up receiving data from SD.
Try to use another line to slave select of SD.
 

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