The alternate output functions identified in Table 5-2are configured by setting the appro- priate bits in the Paralle Port x Function Register.

Table 5-3. Parallel Port x Alternate Functions

Parallel Port x Function Register

(PCFR)

(Address = 0x0055)

 

 

 

(PDFR)

(Address = 0x0065)

 

 

 

(PEFR)

(Address = 0x0075)

 

 

 

(PFFR)

(Address = 0x003D)

 

 

 

(PGFR)

(Address = 0x004D)

Bit(s)

Value

 

Description

 

 

 

 

 

 

0

The corresponding port bit functions normally.

 

 

 

 

7:0

 

The corresponding port bit carries its alternate signal as an output. See Table 5-4

1

below. Only the bits that have alternate functions listed in Table 5-4actually have

 

 

a control bit in these registers. That is, there are four in Port C, four in Port D,

 

 

 

 

eight in Port E, four in Port F, and eight in Port G.

 

 

 

 

 

 

Table 5-4. Parallel Port x Alternate Functions Control Bits

Alternate Output Function

Bit

Port B

Port C

Port D

Port E

Port F

Port G

 

 

 

 

 

 

 

7

/SLAVEATTN, IA5

 

APWM3

I7

PWM3

APWM1

 

 

 

 

 

 

 

6

IA4

TXA

ATXA

I6

PWM2

TXE

 

 

 

 

 

 

 

5

IA3

 

APWM2

I5

PWM1

RCLKE

 

 

 

 

 

 

 

4

IA2

TXB

ATXB

I4

PWM0

TCLKE

 

 

 

 

 

 

 

3

IA1

 

 

I3

 

APWM0

 

 

 

 

 

 

 

2

IA0

TXC

 

I2

 

TXF

 

 

 

 

 

 

 

1

CLKA

 

 

I1

CLKC

RCLKF

 

 

 

 

 

 

 

0

CLKB

TXD

 

I0

CLKD

TCLKF

 

 

 

 

 

 

 

User’s Manual

67

Page 76
Image 76
Jameco Electronics 3000, 2000 manual Parallel Port x Alternate Functions Control Bits