N79E715 Datasheet, PDF (31/189 Pages) List of Unclassifed Manufacturers – Microcontroller

N79E715 Datasheet
MOV
Px.y,C Move carry bit to Px.y.
CLR
Px.y Clear bit Px.y.
SETB
Px.y Set bit Px.y.
The last three seems not obviously read-modify-write instructions but actually they are. They read the
entire port latch value, modify the changed bit, and then write the new value back to the port latch.
9.2 Open Drain Output Configuration
The open drain output configuration turns off all pull-ups and only drives the pull-down transistor of the
port driver when the port latch contains logic 0. To be used as a logic output, a port configured in this
manner should have an external pull-up, typically a resistor tied to V_DD. The pull-down for this mode is
the same as for the quasi-bidirectional mode. The open drain port configuration is shown below.
Port Latch
N
Data
Input Data
Port Pin
Figure 9-2 Open Drain Output
9.3 Push-Pull Output Configuration
The push-pull output configuration has the same pull-down structure as both the open drain and the
quasi-bidirectional output modes, but provides a continuous strong pull-up when the port latch
contains logic 1. The push-pull mode may be used when more source current is needed from a port
output. The push-pull port configuration is shown in Figure 9-2. The two port pins that cannot be
configured are P1.2 (SCL) and P1.3 (SDA). The port pins P1.2 and P1.3 are permanently configured
as open drain outputs. They may be used as inputs by writing ones to their respective port latches.
Additionally, port pins P3.0 and P3.1 are disabled for both input and output if one of the crystal
oscillator options is chosen. Those options are described in the Oscillator section.
When port pins are driven high at reset, they are in quasi-bidirectional mode and therefore do not
source large amounts of current. Every output on the N79E715 may potentially be used as a 38 mA
sink LED drive output. However, there is a maximum total output current for all ports which should not
be exceeded.
All port pins of the N79E715 have slew rate controlled outputs. This is to limit noise generated by
quickly switching output signals. The slew rate is factory set to approximately 10 ns rise and fall times.
Jan. 6, 2016
Page 31 of 189
Revision 1.01