MC68331TS datasheet(35/84 Pages) FREESCALE

35 / 84 page

MC68331TS/D

3.6 General-Purpose Input/Output

SIM pins can be configured as two general-purpose I/O ports, E and F. The following paragraphs de-

scribe registers that control the ports.

A write to the port E data register is stored in the internal data latch and, if any port E pin is configured

as an output, the value stored for that bit is driven on the pin. A read of the port E data register returns

the value at the pin only if the pin is configured as a discrete input. Otherwise, the value read is the value

stored in the register.

The port E data register is a single register that can be accessed in two locations. When accessed at

$YFFA11, the register is referred to as PORTE0; when accessed at $YFFA13, the register is referred

to as PORTE1. The register can be read or written at any time. It is unaffected by reset.

The bits in this register control the direction of the pin drivers when the pins are configured as I/O. Any

bit in this register set to one configures the corresponding pin as an output. Any bit in this register

cleared to zero configures the corresponding pin as an input. This register can be read or written at any

time.

The bits in this register control the function of each port E pin. Any bit set to one configures the corre-

sponding pin as a bus control signal, with the function shown in the following table. Any bit cleared to

zero defines the corresponding pin to be an I/O pin, controlled by PORTE and DDRE.

Data bus bit 8 controls the state of this register following reset. If DATA8 is set to one during reset, the

during reset, this register is set to $00, configuring all port E pins as I/O pins.

Any bit cleared to zero defines the corresponding pin to be an I/O pin. Any bit set to one defines the

corresponding pin to be a bus control signal.

PORTE0, PORTE1 —Port E Data Register

$YFFA11, $YFFA13

NOT USED

PE7

PE6

PE5

PE4

PE3

PE2

PE1

PE0

RESET:

DDRE — Port E Data Direction Register

$YFFA15

NOT USED

DDE7

DDE6

DDE5

DDE4

DDE3

DDE2

DDE1

DDE0

RESET:

PEPAR — Port E Pin Assignment Register

$YFFA17

NOT USED

PEPA7

PEPA6

PEPA5

PEPA4

PEPA3

PEPA2

PEPA1

PEPA0

RESET:

DATA8

Table 16 Port E Pin Assignments

PEPAR Bit

Port E Signal

Bus Control Signal

PEPA7

PE7

SIZ1

PEPA6

PE6

SIZ0

PEPA5

PE5

PEPA4

PE4

PEPA3

PE3

RMC

PEPA2

PE2

AVEC

PEPA1

PE1

DSACK1

PEPA0

PE0

DSACK0

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MC68331TS Scheda tecnica(PDF) 35 Page - Freescale Semiconductor, Inc

MC68331TS Scheda tecnica(HTML) 35 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

Scheda tecnica Scarica

Link URL