R

EM6607

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7.5

PortE

PortE is a 4-bit I/O port where each pad PE(0:3) can be separately configured by software to be either input or output by

writing to the corresponding bit of the CIOPortE control register. The PortE 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

PortC 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).

Input mode is set by writing 0 to the corresponding bit in the CIOPortE register. This results in a high impedance state with

the status of the pin being read from register PortE. Output mode is set by writing 1 to the corresponding bit in the CIOPortE

register. Consequently the output terminal follows the status of the bits in the PortE register. At initial RESET the CIOPortE

register is set to 0, thus setting the port to an input.

7.5.1

PortE registers

Table 25.

PortE Input/Output status register - PortE

Bit

Name

Reset

R/W

Description

3

PE3

-

R/W

PE3 I/O data

2

PE2

-

R /W

PE2 I/O data

1

PE1

-

R/W

PE1 I/O data

0

PE0

-

R /W

PE0 I/O data

Table 26.

PortE Input/Output control register - CIOPortE

Bit

Name

Reset

R/W

Description

3

CIOPE3

0

R/W

PE3 Input/Output select

2

CIOPE2

0

R/W

PE2 Input/Output select

1

CIOPE1

0

R/W

PE1 Input/Output select

0

CIOPE0

0

R/W

PE0 Input/Output select

PE[3:0]

Vdd

2Y

2N

Mask

option

Mask

option

0

Mask

option

1

Mask

option

PortE RD

PG

NG

OE

D

Port E

CIOPE

Figure 11.

Port E