HT48E10_0610 Datasheet, PDF (17/42 Pages) Holtek Semiconductor Inc – I/O Type 8-Bit MTP MCU With EEPROM

HT48E10
The EEPROM data memory is accessed via a
three-wire serial communication interface by writing to
EECR. It is arranged into 128 words by 8 bits. The
EEPROM data memory contains seven instructions:
READ, ERASE, WRITE, EWEN, EWDS, ERAL and
WRAL. These instructions are all made up of 10 bits
data: 1 start bit, 2 op-code bits and 7 address bits.
Before accessing the EEPROM, an initial procedure
should be executed. The following procedures show the
detail procedures step by step.
· Execute the EWEN instruction.
· Execute the WRITE instruction. (The application pro-
grams need to reserve one location for this procedure.
The content of it will be changed after this procedure.)
· Execute the EWDS instruction. (This one is optional. If
you don¢t want to write data to EEPROM immediately,
then disable it to prevent the mis-programming. )
The following is an assembly program example. User
can put them into the POR program. (Note: Please refer
to the application note for the detail of the EWEN,
EWDS and WRITE subroutines.)
mov A,01h
mov BP,A
; set to bank 1
mov A,40h
mov MP1,A
; set MP1 to EECR address
call EWEN
; subroutine to run EWEN
; instructions.
mov A, 7Fh
mov EEADDR, A
mov A, 55h
mov EEDATA, A
call WRITE ; subroutine to run WRITE
; instructions. (write 55h data to
; address 7Fh.)
call EWDS
; subroutine to run EWDS
; Instructions.
; (This one is optional)
By writing CS, SK and DI, these instructions can be
given to the EEPROM. These serial instruction data pre-
sented at the DI will be written into the EEPROM data
memory at the rising edge of SK. During the READ cy-
cle, DO acts as the data output and during the WRITE or
ERASE cycle, DO indicates the BUSY/READY status.
When the DO is active for read data or as a BUSY/
READY indicator the CS pin must be high; otherwise DO
will be in a high state. For successful instructions, CS
must be low after the instruction is sent. After power-on,
the device is by default in the EWDS state. An EWEN in-
struction must be performed before any ERASE or
WRITE instruction can be executed.
The following are the functional descriptions and timing diagrams of all seven instructions.
tC S S
CS
tS K H
SK
tD IS
t D IH
DI
V a lid D a ta
tS K L
V a lid D a ta
tC D S
tC S H
tP D 0
tP D 1
DO
1
Rev. 1.50
17
October 31, 2006