EMS6500 EM Microelectronic, EMS6500 Datasheet - Page 89

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

Copyright  2003 EM Microelectronic-Marin SA
7.2.
7.3.
7.4.
Port B is a bitwise select input output port. The state of port B (address 052H) 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
051H) 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 7-3.
The serial port can be defined as a parallel input port or a parallel output port. When
in either of these modes the possible combinations of the LED states and button
states are the same as those for port B (see Table 7-3 Possible states for an input
output port.).
When in serial mode the ports have the following attributions
The state of the 1Hz, 8Hz and Blink interrupt masks are shown. The symbol
indicates that the interrupt mask is active and the symbol
interrupt mask is inactive.
Port
Out
Clk
LED state
S
In
Port B
Serial Port
Prescaler
Red
Yellow
Red
Yellow
Function
Serial Data In
Serial Clock
Serial Data Out
Status - Chip select (bit 2 reg.054H)
Table 7-3 Possible states for an input output port.
Button
NC
NC
H
L
Table 7-4 Serial port states
State
Port input and high
Port input and low
Port output and high
Port output and low
25
Peripheral Interface
Possible states
Input
Output in master mode
Input in slave mode
Output
Output
indicates that the
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Binder 4.3-01/03 Rev. B/495