MC68HC05B4 Datasheet, PDF (194/298 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

EPROM will not be available for code execution while the E6LAT bit is set. The V_PP6 switching must
occur externally after the E6PGM bit is set, for example under control of a signal generated on a
pin by the programming routine.
Note:
When the part becomes a PROM, only the cumulative programming of bits to logic ‘1’
is possible if multiple programming is made on the same byte.
To allow simultaneous programming of up to eight bytes, these bytes must be in the same group
of addresses which share the same most significant address bits; only the three least significant
bits can change.
E.3.3 EPROM/EEPROM/ECLK control register
EPROM/EEPROM/ECLK control
Address bit 7
$0007
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
E6LAT E6PGM ECLK E1ERA E1LAT E1PGM 0000 0000
E6LAT — EPROM programming latch enable bit
1 (set) – Address and up to eight data bytes can be latched into the EPROM
for further programming providing the E6PGM bit is cleared.
0 (clear) – Data can be read from the EPROM or firmware ROM; the E6PGM bit
is reset to zero when E6LAT is ‘0’.
STOP, power-on and external reset clear the E6LAT bit.
Note:
After the t_ERA1 erase time or t_PROG1 programming time, the E6LAT bit has to be reset
to zero in order to clear the E6PGM bit.
E6PGM — EPROM program enable bit
This bit is the EPROM program enable bit. It can be set to ‘1’ to enable programming only after
E6LAT is set and at least one byte is written to the EPROM. It is not possible to clear this bit using
software but clearing E6LAT will always clear E6PGM.
14
Note:
Table E-2 EPROM control bits description
E6LAT E6PGM
Description
0
0 Read/execute in EPROM
1
0 Ready to write address/data to EPROM
1
1 programming in progress
The E6PGM bit can never be set while the E6LAT bit is at zero.
MOTOROLA
E-6
MC68HC705B16
TPG
MC68HC05B6
Rev. 4