MCP48FVB04 datasheet(78/112 Pages) MICROCHIP

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MCP48FXBX4/8

DS20006362A-page 78

 2020 Microchip Technology Inc.

7.3

Continuous Commands

The devices support the ability to execute commands

continuously. While the CS pin is in the Active state

(VIL), any sequence of valid commands may be

received.

The following example is a valid sequence of events:

CS pin is driven active (VIL).

READ command.

WRITE command (volatile memory).

WRITE command (nonvolatile memory).

CS pin is driven inactive (VIH).

7.4

Commands to Modify the Device

Configuration Bits

The MCP48FXBX4/8 devices support two commands,

which are used to program the device’s Configuration

bits. These commands require a High Voltage (VIHH) on

the HVC pin. The commands are:

• Enable Configuration Bit (High Voltage)

• Disable Configuration Bit (High Voltage)

The Configuration bits are used to inhibit the DAC

values from inadvertent modification. High voltage is

required to change the state of these bits if/when the

DAC values need to be modified.

7.5

High-Voltage Command (HVC)

Signal

The High-Voltage Command (HVC) signal is used to

indicate that the command or sequence of commands

are in the High-Voltage mode. Signals higher than VIHH

(~9.0V) on the LAT/HVC pin puts the device into High-

Voltage mode. High-voltage commands allow the

device’s WiperLock technology and write-protect

features to be enabled and disabled.

TABLE 7-2:

SPI COMMANDS – OVERVIEW AND COMMAND RATE

Command

# of Bit

Clocks(2)

Estimated Peak

Command Rate

(Commands/ms)(5)

Comments

Operation

Code

Mode(1)

C1 C0

1MHz 10 MHz 20 MHz

WRITE Command

No(3) Single

416

833

No(3) Continuous

24 * n

READ Command(4)

No(3) Single

Read frequency can

be up to 10 MHz

No(3) Continuous

24 * n

Enable Configuration

Bit (High Voltage)

Yes

Single

125

1250

2500

Yes

Continuous

8 * n

Disable Configuration

Bit (High Voltage)

Yes

Single

Yes

Continuous

8 * n

Note 1:

Nonvolatile registers can only use the Single mode.

“n” indicates the number of times the command operation is to be repeated.

If the state of the HVC pin is VIHH, then the command is ignored, but a Command Error condition

(CMDERR) will NOT be generated.

This command is used to determine when an EEPROM programming cycle is complete.

The actual voltage output update rate depends on several factors, such as output settling time, code,

reference voltage or load impedance.

Note 1: It is recommended that while the CS pin is

active, only one type of command should

be issued. When changing commands, it

is advisable to take the CS pin inactive,

then force it back to the Active state.

2: Long command strings should be broken

down into shorter command strings. This

reduces the probability of noise on the

SCK pin, corrupting the desired SPI

command string.

Note 1: There is a required delay after the HVC

pin is driven to the VIHH level on the first

edge of the SCK pin.

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