User manual

SPI Master Communications

FIGURE 5-4: SPI BASIC OPERATIONS

5.6.1 Basic Communications – Serial EEPROM Example

Figures 5-5 through 5-7 demonstrates how to communicate with a 25LC020A SPI

serial EEPROM. Refer to the 25LC020A Data Sheet (DS21833) for a detailed

explanation of its SPI communications.

Before data can be written to the 25LC020A, the write enable (WREN) latch must be

set. This requires that CS

be enabled, command 0x06 transmitted, and CS disabled.

Figure 5-5 shows only Group 0 enabled. All other groups are disabled. Clicking on the

Execute button will transmit only the WREN command. The command will be logged

in the Transactions window.

FIGURE 5-5: SEEPROM EXAMPLE – WREN COMMAND

Once the WREN latch has been enabled, data can be written to the 25LC020A.

Figure 5-6 shows that Group 0 has been disabled, and Group 1 enabled. Clicking on

the Execute button will send the Write command (0x02), the memory address (0x00),

followed by three bytes of data: 0xAA, 0xBB, and 0xCC. The command will be logged

in the Transactions window.