C8051F960-B-GM Datasheet, PDF (127/492 Pages) Silicon Laboratories – Ultra Low Power 128K, LCD MCU Family

C8051F96x
SFR Definition 9.1. PSBANK: Program Space Bank Select
Bit
7
6
5
4
3
2
1
0
Name
COBANK[1:0]
IFBANK[1:0]
Type ^R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
1
0
0
0
1
SFR Page = All Pages; SFR Address = 0x84
Bit
Name
Function
7:6 Reserved Read = 00b, Must Write = 00b.
5:4 COBANK[1:0] Constant Operations Bank Select.
These bits select which flash bank is targeted during constant operations (MOVC
and flash MOVX) involving address 0x8000 to 0xFFFF.
00: Constant Operations Target Bank 0 (note that Bank 0 is also mapped between
0x0000 to 0x7FFF).
01: Constant operations target Bank 1.
10: Constant operations target Bank 2.
11: Constant operations target Bank 3.
3:2 Reserved Read = 00b, Must Write = 00b.
1:0 IFBANK[1:0] Instruction Fetch Operations Bank Select.
These bits select which flash bank is used for instruction fetches involving address
0x8000 to 0xFFFF. These bits can only be changed from code in Bank 0.
00: Instructions fetch from Bank 0 (note that Bank 0 is also mapped between
0x0000 to 0x7FFF).
01: Instructions fetch from Bank 1.
10: Instructions fetch from Bank 2.
11: Instructions fetch from Bank 3.
Note:
1. COBANK[1:0] and IFBANK[1:0] should not be set to (10b) or (11b) on the C8051F964/5/6/7/8/9 devices.
2. On devices with 64 kB of flash or less, keep PSBANK at its default setting of 0x11.
9.1.1. MOVX Instruction and Program Memory
The MOVX instruction in an 8051 device is typically used to access external data memory. On the
C8051F96x devices, the MOVX instruction is normally used to read and write on-chip XRAM, but can be
re-configured to write and erase on-chip flash memory space. MOVC instructions are always used to read
flash memory, while MOVX write instructions are used to erase and write flash. This flash access feature
provides a mechanism for the C8051F96x to update program code and use the program memory space for
non-volatile data storage. Refer to Section “18. Flash Memory” on page 244 for further details.
9.2. Data Memory
The C8051F96x device family includes 8448 bytes (C8051F960/1/2/3/4/5/6/7) or 4352 bytes
(C8051F968/9) of RAM data memory. 256 bytes of this memory is mapped into the internal RAM space of
the 8051. 8192 or 4096 bytes of this memory is on-chip “external” memory. The data memory map is
shown in Figure 9.1 for reference.
9.2.1. Internal RAM
Rev. 1.0
127