ST7282A5 - ST7282B5 - ROM FROM EPROM
Figure 9. Peripheral Interface Configuration of Serial I/O
DOUT / PA7
PP / OD
OPR
MUX
0
1
DR
OUT
SDA / PA6
IN
DR
SERIAL
I/O
CLOCK
SCL / PA5
DR
INTERFA C.DS4
2.8 RAM
The RAM is located in the address range A0H-
3FFH.
300H-3FFH may be used as Stack area.
2.9 EEPROM
The 512 bytes EEPROM is located at addresses
0E00 - 0FFF. 2 cells of 256 bytes each or one cell
of 512 bytes may be used. EEPROM control regis-
ter EECR (adr. 014H) is used to control the differ-
ent operation modes of the range 0E00H - 0EFFH,
EEPROM control register EECR2 (adr. 015H) that
of range 0F00H - 0FFFH. Some of its bits are read
only, some are write only. So no single bit instruc-
tions are allowed.
To avoid destruction of data during power up or
down, the reset pin directly desactivates the
chargepump of EEPROM cells.
The EEPROM can be used for data storage only,
no program execution and no read modify write in-
structions (single bit, increment, decrement) are
possible.
After bit E2LAT of EECR goes to low, there should
not be a read operation during the next 20 µsec.
A parallel programming mode for 8 bytes is availa-
ble. No clear is needed before a write.
Two cells of 256 bytes are used, parallel program-
ming of bytes in each cell is possible. This should
be avoided however, to keep software compatitility
between all future versions and ROM versions,
that have only one physical register, that will be
addressed through two different addresses 14H
and 15H.
Family
ST7
Issuer Ref.
PG-RO
Chrono
97115
7282A5B5
March 26, 1997
Previous Ref
Edition
Target C
Page 19/23