Maxim Integrated 78Q8430 Software Driver - Manual (Page 43)

UG_8430_004 78Q8430 Software Driver Development Guidelines
Rev. 1.0 43
8 EEPROM Operations
The 78Q8430 provides logic for reading and writing an optional external EEPROM or ROM device. Refer
to the 78Q8430 Data Sheet for supported devices. EEPROM Erase, Write, and Read procedures are
described in this section.
8.1 EEPROM Erase
Use the following procedure to erase the EEPROM:
STEP 1: Write to PRCR.
Fill the PRCR Operation field with the Erase command (b11) and set the PRCR Busy bit.
STEP 3: Read PRCR.
STEP 4: Repeat STEP 3 until the PRCR Busy bit is clear.
8.2 EEPROM Write Access
Use the following procedure to write a value to the EEPROM:
STEP 1: Write the data to PRDR.
Write the desired data to the lower 16 bits of PRDR.
STEP 2: Write to PRCR.
Fill the PRCR PROM Addr field with the EEPROM address to write. Fill the Operation field with the
Write command (b01) and set the Busy bit.
STEP 3: Read PRCR.
STEP 4: Repeat STEP 3 until the PRCR Busy bit is clear.
8.3 EEPROM Read Access
Use the following procedure to read a value from the EEPROM:
STEP 1: Write to PRCR.
Fill the PRCR PROM Addr field with the EEPROM address to read. Fill the Operation field with the
Read command (b10) and set the Busy bit.
STEP 2: Read PRCR.
STEP 3: Repeat STEP 3 until the PRCR Busy bit is clear.
STEP 4: Read the EEPROM value from PRDR.
The EEPROM data will be in the lower 16 bits.