LOADING SEQUENCE TO DRIVE A 4

-DIGIT DISPLAY

Steps

1

Turn CE low

2

Clock in 8 bits of data for digit 1

3

Clock in 8 bits of data for digit 2

4

Clock in 8 bits of data for digit 3

5

Clock in 8 bits of data for digit 4

6

Clock in 8 bits of data for special segment and control

function of BPC and BPA

0011SP4

SP3

SP2

SP1

7

Turn CS high

Note

CS may be turned high after any step For example to

load only 2 digits of data do steps 1 2 3 and 7

CS must make a high to low transition before loading data in

order to reset internal counters

LOADING SEQUENCE TO DRIVE AN

8

-DIGIT DISPLAY

Two or more COP472-3’s may be connected together to

drive additional segments An eight digit multiplexed display

is shown in

Figure 7 The following is the loading sequence

to drive an eight digit display using two COP472-3’s The

right chip is the master and the left the slave

Steps

1

Turn CS low on both COP472-3’s

2

Shift in 32 bits of data for the slave’s four digits

3

Shift in 4 bits of special segment data a zero and three

ones

1110SP4

SP3

SP2

SP1

This synchronizes both the chips and BPA is oscillator

input Both chips are now stopped

4

Turn CS high to both chips

5

Turn CS low to master COP472-3

6

Shift in 32 bits of data for the master’s 4 digits

7

Shift in four bits of special segment data a one and

three zeros

0001SP4

SP3

SP2

SP1

This sets the master COP472-3 to BPA as a normal

backplane output and BPC as oscillator output Now

both the chips start and run off the same oscillator

8

Turn CS high

The chips are now synchronized and driving 8 digits of dis-

play To load new data simply load each chip separately in

the normal manner keeping the correct status bits to each

COP472-3 (0110 or 0001)

TLDD6932 – 6

FIGURE 6 System Diagram – 4

Digit Display

TLDD6932 – 7

FIGURE 7 System Diagram – 8

Digit Display

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