VRS1000 데이터 시트보기 (PDF) - Unspecified
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VRS1000 Datasheet PDF : 47 Pages
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VRS1000
VERSA
Datasheet Rev 1.6
TABLE 19: LIST OF INSTRUCTIONS THAT READ AND MODIFY THE PORT USING REGISTER
VALUES
Instruction Function
ANL
Logical AND ex: ANL P0, A
ORL
Logical OR ex: ORL P2, #01110000B
XRL
Exclusive OR ex: XRL P1, A
JBC
Jump if the bit of the port is set to 0
CPL
Complement one bit of the port
INC
Increment the port register by 1
DEC
Decrement the port register by 1
DJNZ
Decrement by 1 and jump if the result
is not equal to 0
MOV P.,C Copy the held bit C to the port
CLR P.x Set the port bit to 0
SETB P.x Set the port bit to 1
Port Operation Timing
Writing to a Port (Output)
When an operation induces a modification of the
content in a port register, the new value is placed at
the output of the D flip-flop during the T12 period of the
last machine cycle that the instruction needed to
execute.
It is important to note, however, that the output stage
only samples the output of the registers on the P1
phase of each period. It follows that the new value only
appears at the output after the T12 period of the
following machine cycle.
Reading a Port (Input)
The reading of an I/O pin takes place:
o During T9 cycle for P0, P1
o During T10 cycle for P2, P3
When the ports are configured as I/Os
In order to get sampled, the signal duration present on
the I/O inputs must have a duration longer than
Fosc/12.
I/O Ports Driving Capability
The maximum allowable continuous current that the
device can sink on I/O port is defined by the following
Maximum sink current on one given I/O
Maximum total sink current for P0
Maximum total sink current for P1, 2, 3
Maximum total sink current for P4
Maximum total sink current on all I/O
10mA
26mA
15mA
20mA
91mA
On the VRS1000, the Port4 output buffers can sink up
to 20mA, which render possible direct driving of LED
displays.
It is not recommended to exceed the sink current
expressed in the above table. Doing so is likely to
make the low-level output voltage exceed the device’s
specification and it is likely to affect the device’s
reliability.
The VRS1000 I/O ports are not designed to source
current.
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