EMS6500 EM Microelectronic, EMS6500 Datasheet - Page 108

• Manufacturer Part Number: EMS6500
• Description: Microcontroller Development System 4-bit (Emmon), Simulators 4-bit
• Manufacturer: EM Microelectronic

Copyright  2003 EM Microelectronic-Marin SA
10.2. Port B
10.3. Port C
10.4. Serial Write Buffer (SWB)
The state of the interrupt mask for port A (address 062H) is shown next to the
button. The possible interrupt mask states are shown in Table 11-2.
Port B is a bitwise select input output port. The state of port B (address 056H) is
shown by the LED and buttons. When the port is input the state can be changed
using the corresponding push buttons. When the port is set to output (address
076H) the button is set to NC (not connected) and the LED indicates the state of the
output port. Consequently the possible combinations for the LED and button states
are shown in Table 11-3.
Port C is similar to Port B when used as general I/O Port, but it can also overtake
the signals of the SWB, as explained below.
When the Serial Write Buffer is enabled, Port C-bit 0 overtakes the Clock Signal and
Port C-bit 1 the Data Signal of the SWB.
LED state
Symbol
Red
Yellow
Red
Yellow
Fig. 10-2. Representation of the SWB on the IO-Panel
State
Interrupt generated on the falling edge of the port
Interrupt generated on the rising edge of the port
Interrupt disabled
Table 10-2 Representation of possible IRQ mask states.
Table 10-3 Possible states for input output port.
Button
NC
NC
H
L
State
Port input and high
Port input and low
Port output and high
Port output and low
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Peripheral Interface
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