EM6607 EM Microelectronic, EM6607 Datasheet - Page 15

• Manufacturer Part Number: EM6607
• Description: Ultra-low power microcontroller
• Manufacturer: EM Microelectronic

7.2
Port B is a 4-bit general-purpose I/O port. Outputs on this port are high current outputs. Each bit PB(0:3) can be separately
configured by software to be either input or output by writing to the corresponding bit of the CIOPortB control register. The
PortB register is used to read data when in input mode and to write data when in output mode. On each terminal controlled
Pull-Up/Down resistor can be selected by metal option, which are active only when selected as input. Special case is when
we want to use internal Strong Pull-Up resistor also when PortB terminal is declared as N-channel open drain output and
internal Pull-Up resistor is used to pull up the output (not-controlled Pull-Up). This is a special option “sod” = strong Pull-Up
for Open drain- active all the time (when terminal is input or output).
Writing 0 to the corresponding bit in the CIOPortB register sets input mode. This results in a high impedance state with the
status of the pin being read from register PortB. Writing 1 to the corresponding bit in the CIOPortB register sets output
mode. Consequently the output terminal follows the status of the bits in the PortB register. At initial RESET the CIOPortB
register is set to 0, thus setting the port to input. Additionally, PB0 can also be used as a three-tone buzzer output. For
details see section 7, Buzzer.
7.2.1
Table 16.
Table 17.
Figure 8.
If metal mask option 3Y (Input blocked when Output) is used and port is declared as Output (CIOPortB = 1111b) the real
port information cannot be read directly. In this case no direct logic operations (like AND PortB) on Output ports are
possible. This logic operation can be made with an image of the Port saved in the RAM which we store after on the output
port. This is valid for PortB, PortC and PortD when declared as output and the metal Option 3Y is used. In the case of metal
option 3N selected direct logic operations on output ports are possible.
If OEBsleepRes bit in Option2 register is set to “1” (Output Hi-Z in SLEEP mode) the active Output will go tri-state when
the circuit goes into SLEEP mode. In the case of OEBsleepRes at “0”, output stays active also in the SLEEP mode.
Copyright © 2005, EM Microelectronic-Marin SA
Bit
3
2
1
0
Bit
3
2
1
0
PortB
PortB registers
PB[3:0]
PortB input/output status register - PortB
PortB Input/Output control register - CIOportB
Port B
R
Name
PB3
PB2
PB1
PB0
Name
CIOPB3
CIOPB2
CIOPB1
CIOPB0
0
1
option
option
Mask
Mask
Vdd
Reset
-
-
-
-
Reset
0
0
0
0
2Y
2N
R/W
R/W
R /W
R/W
R /W
R/W
R/W
R/W
R/W
R/W
option
option
Mask
Mask
PG
NG
OE
Description
Description
PB3 I/O data
PB2 I/O data
PB1 I/O data
PB0 I/O data
PB3 Input/Output select
PB2 Input/Output select
PB1 Input/Output select
PB0 Input/Output select
3Y
3N
D
15
option
option
Mask
Mask
CIOportB
PortB RD
Port B
OEBsleepRes
Sleep
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