8XC251SA, SB, SP, SQ USER’S MANUAL
A-66
Operation:
JB
(PC)
←
(PC) + 3
IF (bit) = 1
THEN
(PC)
←
(PC) + rel
JBC bit51,rel
JBC bit,rel
Function:
Jump if bit is set and clear bit
Description:
If the specified bit is one, branch to the specified address; otherwise proceed with the next
instruction. The bit is not cleared if it is already a zero. The branch destination is computed
by adding the signed relative displacement in the third instruction byte to the PC, after incre-
menting the PC to the first byte of the next instruction.
Note: When this instruction is used to test an output pin, the value used as the original data
is read from the output data latch, not the input pin.
Flags:
Example:
The accumulator contains 56H (01010110B). After the instruction sequence
JBC ACC.3,LABEL1
JBC ACC.2,LABEL2
the accumulator contains 52H (01010010B) and program execution continues at label
LABEL2.
Variations
JBC bit51,rel
Binary Mode
Source Mode
Not Taken
Taken
Not Taken
Taken
Bytes:
3
3
3
3
States:
4
7
4
7
Hex Code in:
Binary Mode = [Encoding]
Source Mode = [Encoding]
Operation:
JBC
(PC)
←
(PC) + 3
IF (bit51) = 1
THEN
(bit51)
←
0
(PC)
←
(PC) + rel
CY
AC
OV
N
Z
—
—
—
—
—
[Encoding]
0 0 0 1
0 0 0 0
bit addr
rel. addr
Summary of Contents for 8XC251SA
Page 2: ......
Page 3: ...May 1996 8XC251SA 8XC251SB 8XC251SP 8XC251SQ Embedded Microcontroller User s Manual...
Page 18: ......
Page 19: ...1 Guide to This Manual...
Page 20: ......
Page 30: ......
Page 31: ...2 Architectural Overview...
Page 32: ......
Page 41: ...3 Address Spaces...
Page 42: ......
Page 63: ...4 Device Configuration...
Page 64: ......
Page 81: ...5 Programming...
Page 82: ......
Page 102: ......
Page 103: ...6 Interrupt System...
Page 104: ......
Page 120: ......
Page 121: ...7 Input Output Ports...
Page 122: ......
Page 132: ......
Page 133: ...8 Timer Counters and Watchdog Timer...
Page 134: ......
Page 153: ...9 Programmable Counter Array...
Page 154: ......
Page 170: ......
Page 171: ...10 Serial I O Port...
Page 172: ......
Page 187: ...11 Minimum Hardware Setup...
Page 188: ......
Page 197: ...12 Special Operating Modes...
Page 198: ......
Page 206: ......
Page 207: ...13 External Memory Interface...
Page 208: ......
Page 239: ...14 Programming and Verifying Nonvolatile Memory...
Page 240: ......
Page 250: ......
Page 251: ...A Instruction Set Reference...
Page 252: ......
Page 390: ......
Page 391: ...B Signal Descriptions...
Page 392: ......
Page 400: ......
Page 401: ...C Registers...
Page 402: ......
Page 436: ......
Page 437: ...Glossary...
Page 438: ......
Page 446: ......
Page 447: ...Index...
Page 448: ......
Page 458: ......