ST6369 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST6369' PDF : 71 Pages View PDF
ST6369
MEMORY SPACES (Continued)
Data RAM/EEPROM
In the ST6369 64 bytes of data RAM are directly ad-
dressable in the data space from 80H to BFH ad-
dresses. The additional 192 bytes of RAM, the 384
bytes of EEPROM can be addressed using the
banks of 64 bytes located between addresses 00H
and 3FH. The selection of the bank is done by pro-
gramming the Data RAM Bank Register (DRBR)
located at the E8H address of the Data Space. In
this way each bank of RAM, EEPROM can select
64 bytes at a time. No more than one bank should
be set at a time.
Figure 16. Data RAM Bank Register
DRBR
Data RAM
Bank Register
(E8H, Write Only)
D7 D6 D5 D4 D3 D2 D1 D0
DRBR0
DRBR1
DRBR2
DRBR3
DRBR4
DRBR5
DRBR6
DRBR7
DRBR7,DRBR1,DRBR0. These bits select the
EEPROM pages.
DRBR4,DRBR3,DRBR2. Each of these bits, when
set, will select one RAM page.
This register is undefined after reset.
Table 5 summarizes how to set the Data RAM
Bank Register in order to select the various banks
or pages.
Note :
Care is required when handling the DRBR as it is
write only. For this reason, it is not allowed to
change the DRBR contents while executing inter-
rupts drivers, as the driver cannot save and than
restore its previous content. If it is impossible to
avoid the writing of this register in interrupts driv-
ers, an image of this register must be saved in a
RAM location, and each time the program writes
the DRBR it writes also the image register.
The image register must be written first, so if an in-
terrupt occurs between the two instructions the
DRBR is not affected.
EEPROM Description
The data space of ST6369 family from 00H to 3FH
is paged as described in Table 5. 384 bytes of
EEPROM located in six pages of 64 bytes (pages
0,1,2,3,4 and 5, see Table 5).
Table 5. Data RAM Bank Register Set-up
Hex.
01H
02H
03H
81H
82H
83H
04H
08H
10H
DRBR Value
Binary
0000 0001
0000 0010
0000 0011
1000 0001
1000 0010
1000 0011
0000 0100
0000 1000
0001 0000
Selection
EEPROM Page 0
EEPROM Page 1
EEPROM Page 2
EEPROM Page 3
EEPROM Page 4
EEPROM Page 5
RAM Page 2
RAM Page 3
RAM Page 4
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