Rev. 1.71
34
April 11, 2017
Rev. 1.71
35
April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
EEC Register
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
WREN
WR
RDEN
RD
R/W
—
—
—
—
R/W
R/W
R/W
R/W
POR
—
—
—
—
0
0
0
0
B
it 7 ~ 4
Unimplemented, read as "0"
B
it 3
WREN
: Data EEPROM Write Enable
0: Disable
1: Enable
This is the Data EEPROM Write Enable Bit which must be set high before Data EEPROM write
operations are carried out. Clearing this bit to zero will inhibit Data EEPROM write operations.
B
it 2
WR
: EEPROM Write Control
0: Write cycle has finished
1: Activate a write cycle
This is the Data EEPROM Write Control Bit and when set high by the application program will
activate a write cycle. This bit will be automatically reset to zero by the hardware after the write
cycle has finished. Setting this bit high will have no effect if the WREN has not first been set
high.
B
it 1
RDEN
: Data EEPROM Read Enable
0: Disable
1: Enable
This is the Data EEPROM Read Enable Bit which must be set high before Data EEPROM read
operations are carried out. Clearing this bit to zero will inhibit Data EEPROM read operations.
B
it 0
RD
: EEPROM Read Control
0: Read cycle has finished
1: Activate a read cycle
This is the Data EEPROM Read Control Bit and when set high by the application program will
activate a read cycle. This bit will be automatically reset to zero by the hardware after the read
cycle has finished. Setting this bit high will have no effect if the RDEN has not first been set high.
Note: The WREN, WR, RDEN and RD can not be set to “1” at the same time in one instruction. The
WR and RD can not be set to “1” at the same time.
Reading Data from the EEPROM
To read data from the EEPROM, the read enable bit, RDEN, in the EEC register must first be set
high to enable the read function. The EEPROM address of the data to be read must then be placed
in the EEA register. If the RD bit in the EEC register is now set high, a read cycle will be initiated.
Setting the RD bit high will not initiate a read operation if the RDEN bit has not been set. When
the read cycle terminates, the RD bit will be automatically cleared to zero, after which the data can
be read from the EED register. The data will remain in the EED register until another read or write
operation is executed. The application program can poll the RD bit to determine when the data is
valid for reading.
