sh6616 SinoWealth Micro-Electronics Corp. Ltd, sh6616 Datasheet - Page 6

• Manufacturer Part Number: sh6616
• Description: 16k 4-bit Microcontroller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

3. ROM
SH6616 can address up to 24K X 16 bit words of program area from $000 to $5FFF.
ROM SPACE in the system is 24576 X 16 bits.
3.1. Interrupt Vector Address Area ($000 to $004)
The program is sequentially executed. An area from address $000 through $004 is reserved for special interrupt service
routines when starting execution of a vector address.
* JMP can be replaced by any other instruction.
3.2. Table Data Reference
Table Data can be stored in program memory and can be referenced by using Table Branch (TJMP) and Return Constant
(RTNW) instructions. The Table Branch Register (TBR) and Accumulator (AC) are placed by an offset address in program
ROM. TJMP instruction branch is placed into address ((PC11 - PC8) X (2
to return look-up value into (TBR, AC). ROM code bit7-bit4 is placed into TBR and bit3-bit0 into AC.
3.3. Bank Switch Mapping
Program Counter (PC11 - PC0) can only address 4K of ROM space. The bank switch technique is used to extend the CPU
address space. The lower 2K of the CPU addressing space maps to lower 2K of ROM space (BANK0). The upper 2K of the
CPU addressing space maps to one of the eleven banks (BANK 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A) of the upper 22K of ROM.
(according to the Bank Register)
The bank switch mapping is as follows:
000 - 7FF
800 - FFF
000 - 7FF
800 - FFF
Address
Address
CPU
CPU
Address
$000
$001
$002
$003
$004
ROM Space,
ROM Space,
0800 - 0FFF
0000 - 07FF
0000 - 07FF
4000 - 47FF
$1FH = 0
(BANK 0)
(BANK 1)
$1FH = 7
(BANK 0)
(BANK 8)
ROM Space,
ROM Space,
4800 - 4FFF
0000 - 07FF
1000 - 17FF
0000 - 07FF
(BANK 0)
(BANK 2)
(BANK 0)
(BANK 9)
$1FH = 1
$1FH = 8
Instruction
JMP
JMP
JMP
JMP
ROM Space,
ROM Space,
1800 - 1FFF
0000 - 07FF
0000 - 07FF
5000 - 57FF
(BANK 10)
(BANK 0)
(BANK 3)
(BANK 0)
$1FH = 2
$1FH = 9
6
ROM Space,
ROM Space,
5800 - 5FFF
0000 - 07FF
2000 - 27FF
0000 - 07FF
(BANK 11)
(BANK 0)
(BANK 4)
$1FH = A
(BANK 0)
$1FH = 3
Jump to RESET
Jump to Base Timer
Jump to TIMER0
Reserved
Jump to PORTB
8
Function
) + (TBR, AC)). The address is determined by RTNW
ROM Space,
2800 - 2FFF
0000 - 07FF
$1FH = 4
(BANK 0)
(BANK 5)
ROM Space,
0000 - 07FF
3000 - 37FF
(BANK 0)
(BANK 6)
$1FH = 5
ROM Space,
0000 - 07FF
3800 -3FFF
SH6616
$1FH = 6
(BANK 0)
(BANK 7)