NEC PD754244 Manuel D’Utilisation

User’s Manual  U10676EJ3V0UM

The bit sequential buffer (BSB) is a special data memory used for bit manipulation.  It can manipulate bits by

sequentially changing the address and bit specification.  Therefore, this buffer is useful for processing data with a

long bit length in bit units.

This data memory is configured of 16 bits and can be addressed by a bit manipulation instruction in the pmem.@L

addressing mode.  Its bits can be indirectly specified by the L register.  The processing can be executed by only

incrementing or decrementing the L register in a program loop and by moving the specified bit sequentially.

3

2

1

0

BSB3

FC3H

L = FH

L = CH

3

2

1

0

BSB2

L = BH

L = 8H

3

2

1

0

BSB1

L = 7H

L = 4H

3

2

1

0

BSB0

L = 3H

L = 0H

FC2H

FC1H

FC0H

INCS L

DECS L

L register

Symbol

Bit

Address

Remarks 1. The specified bit is moved according to the L register in the pmem.@L addressing mode.

2. BSB can be manipulated at any time in the pmem.@L addressing mode, regardless of the

specification of MBE and MBS.

The data in this buffer can also be manipulated even in direct addressing mode.  By using 1-, 4-, or 8-bit direct

addressing mode and pmem.@L addressing mode in combination, 1-bit data can be successively input or output.

To manipulate BSB in 8-bit units, the higher and lower 8 bits are manipulated by specifying BSB0 and BSB2.