MCP47CMB02 datasheet(65/124 Pages) MICROCHIP

65 / 124 page

 2018-2019 Microchip Technology Inc.

DS20006089B-page 65

MCP47CXBXX

5.4

Latch Pin (LAT)

The Latch pin controls when the Volatile DAC register

value is transferred to the DAC wiper. This is useful for

applications that need to synchronize the wiper(s)

updates to an external event, such as zero-crossing or

updates to the other wipers on the device. The LAT pin

is asynchronous to the serial interface operation.

When the LAT pin is high, transfers from the Volatile

DAC register to the DAC wiper are inhibited. The Volatile

DAC register value(s) can continue to be updated.

When the LAT pin is low, the Volatile DAC register

value is transferred to the DAC wiper.

Figure 5-8 shows the interaction of the LAT pin and the

loading of the DAC Wiper x (from the Volatile DAC

pin is held low, the corresponding DAC wiper is

updated as soon as the Volatile DAC register value is

updated.

FIGURE 5-8:

LAT and DAC Interaction.

The LAT pin allows the DAC wiper to be updated to an

external

event

and

have

multiple

DAC

channels/devices update at a common event.

Since the DAC Wiper x is updated from the Volatile

DAC Register x, all DACs that are associated with a

given LAT pin can be updated synchronously.

If the application does not require synchronization, then

this signal should be tied low.

Figure 5-9 shows two cases of using the LAT pin to

control when the Wiper register is updated relative to

the value of a sine wave signal.

FIGURE 5-9:

Example Use of LAT Pin Operation.

Note:

This allows both the Volatile DAC0 and

DAC1 registers to be updated while the

LAT pin is high, and to have outputs

synchronously updated as the LAT pin is

driven low.

Write Command

DAC Wiper x

16 Clocks

LAT

SYNC

Transfer

Serial Shift Reg.

Data

(internal signal)

LAT SYNC

Transfer

Data

Comment

No Transfer

Vol. DAC Register x

 DAC Wiper x

No Transfer

Vol. DAC Register x

Case 1: Zero-Crossing of Sine Wave to Update the Volatile DAC0 Register (using LAT pin)

Case 2: Fixed-Point Crossing of Sine Wave to Update the Volatile DAC0 Register (using LAT pin)

Indicates where LAT pin pulses are active (Volatile DAC0 register updated)

MCP47CMB02 Datasheet(PDF) 65 Page - Microchip Technology

MCP47CMB02 Datasheet(HTML) 65 Page - Microchip Technology

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 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL