Texas Instruments MSP50C614 manual Peripheral Functions

Models: MSP50C614

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I/O

is 0x00 (all inputs). The state of the data registers after RESET low is unknown (input state provided by external hardware).

The 8-bit width is the true size of the mapped location. This is independent of the address spacing, which is greater than 8-bits. When writing to any of the locations in the I/O address map, therefore, the bit-masking need only extend across 8 bits. Within a 16-bit accumulator, the desired bits should be right-justified. When reading from these locations to a 16-bit accumulator, the IN instruction automatically clears the extra bits in excess of 8. The desired bits in the result will be right-justified within the accumulator.

The following table shows the bit locations of the I/O port mapping:

 

 

(8-bit wide location)

 

 

 

 

 

 

07

06

05

04

03

02

01

00

 

 

 

 

 

 

 

 

 

 

 

A port data register . . . . . address 0x00

A7

A6

A5

A4

A3

A2

A1

A0

 

 

 

 

 

 

 

 

 

 

A port control register . . . address 0x04

 

C

C

C

C

C

C

C

C

 

 

 

 

 

 

 

 

 

 

B port data register . . . . . address 0x08

B7

B6

B5

B4

B3

B2

B1

B0

 

 

 

 

 

 

 

 

 

 

B port control register . . . address 0x0C

 

C

C

C

C

C

C

C

C

 

 

 

 

 

 

 

 

 

 

C port data register . . . . . address 0x10

C7

C6

C5

C4

C3

C2

C1

C0

 

 

 

 

 

 

 

 

 

 

C port control register . . . address 0x14

 

C

C

C

C

C

C

C

C

 

 

 

 

 

 

 

 

 

 

D port data register . . . . . address 0x18

D7

D6

D5

D4

D3

D2

D1

D0

 

 

 

 

 

 

 

 

 

 

D port control register² . . address 0x1C

 

C

C

C

C

C

C

C

C

 

 

 

 

 

 

 

 

 

 

E port data register . . . . . address 0x20

E7

E6

E5

E4

E3

E2

E1

E0

 

 

 

 

 

 

 

 

 

 

E port control register . . . address 0x24

 

C

C

C

C

C

C

C

C

 

 

 

 

 

 

 

 

 

 

 

 

A7, B7, C7, D7, E7

: data register

 

 

 

 

 

 

 

 

 

 

C

: control register (0 = IN, 1 = OUT)

 

 

 

 

 

0x00 : state of control register after RESET low

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

²Ports D4 and D5 may be dedicated to the Comparator function, if the Comparator Enable bit is set. If so, then bits 4 and 5 of the D port Control register must be CLEAR. Please refer to Section 3.3, Comparator, for details.

Port D0 is connected to the branch condition COND1. Port D1 is connected to the branch condition COND2, assuming the comparator is disabled. Please refer to Section 3.1.4, Branch on D Port, (and to Section 3.3, Comparator) for more information. External interrupts can be caused by transitions on ports D2, D3, D4, and D5. The interrupts associated with the D port are supported whether those pins are programmed as inputs or as outputs.

Peripheral Functions

3-3

Page 73
Image 73
Texas Instruments MSP50C614 manual Peripheral Functions