MCP47FXB2XT-EST datasheet(80/124 Pages) MICROCHIP

80 / 124 page

MCP47FXBX4/8

DS20006368A-page 80

 2020 Microchip Technology Inc.

7.1

Write Command

(Normal and High-Voltage)

WRITE commands are used to transfer data to the

desired memory location (from the host controller). The

WRITE command can be issued to both volatile and

nonvolatile memory locations.

WRITE commands can be structured as either single or

continuous. The continuous format allows the fastest

data update rate for the device’s memory locations, but

it is not supported for nonvolatile memory locations.

The format of the command is shown in Figure 7-1

(single)

and

Figure 7-3

(continuous).

For

the

ACK/NACK behavior, see Figure 7-2.

A WRITE command to a volatile memory location

changes that location after a properly formatted WRITE

command and the A/A clock has been received.

A WRITE command to a nonvolatile memory location

starts an EEPROM write cycle only after a properly for-

matted WRITE command has been received and the

Stop condition has occurred.

7.1.1

SINGLE WRITE TO VOLATILE

MEMORY

For volatile memory locations, data are written to the

MCP47FXBX4/8 after every data word transfer (during

the Acknowledge). If a Stop or Restart condition is

generated during a data transfer (before the A), the

data will not be written to the MCP47FXBX4/8. After the

A bit, the master can initiate the next sequence with a

Stop or Restart condition.

Refer to Figure 7-1 for the byte write sequence.

7.1.2

SINGLE WRITE TO NONVOLATILE

MEMORY

The sequence to write to a single nonvolatile memory

location is the same as a single write to a volatile

memory with the exception that the EEPROM write

cycle (tWC) is started after a properly formatted

command, including the Stop bit, if received. After the

Stop condition occurs, the serial interface may

immediately be re-enabled by initiating a Start

condition.

During an EEPROM write cycle, access to the volatile

memory is allowed when using the appropriate com-

mand sequence. Commands that address nonvolatile

memory are ignored until the EEPROM write cycle (twc)

completes. This allows the host controller to operate on

the volatile DAC registers.

Figure 7-1 shows the command format for a single

write to volatile or nonvolatile memory location.

7.1.3

CONTINUOUS WRITES TO

VOLATILE MEMORY

A Continuous Write mode of operation is possible when

writing to the device’s volatile memory registers (see

Table 7-2). This Continuous Write mode allows writes

without a Stop or Restart condition or repeated trans-

missions of the I2C Control Byte. Figure 7-3 shows the

sequence for three continuous writes. The writes do not

need to be to the same volatile memory address. The

sequence ends with the Master sending a Stop or

Restart condition.

7.1.4

CONTINUOUS WRITES TO

NONVOLATILE MEMORY

If a continuous write is attempted on a nonvolatile

memory, the missing Stop condition will cause the

command to be an error condition (A). A Start bit is

required to reset the command state machine.

7.1.5

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 operational state. HVC

commands allow the device’s WiperLock Technology

and write protect features to be enabled and disabled.

Note 1: Writes to certain memory locations

depend on the state of the WiperLock™

Technology status bits.

2: During device communication, if the

device address/command combination is

invalid or an unimplemented device

address is specified, the MCP47FXBX4/8

will NACK that byte. To reset the I2C state

machine, the I2C communication must

detect a Start bit.

Note:

The EEWA status bit indicates if an

EEPROM write cycle is active (see

TABLE 7-2:

VOLATILE MEMORY

ADDRESSES

Address

Quad-Channel

Octal-Channel

00h-03h

Yes

04h-07h

Yes

08h

Yes

09h

Yes

0Ah

Yes

Note:

Writes to a volatile DAC register will not

transfer to the output register until the LAT

(HVC) pin is transitioned from the VIHHEN

voltage to a VIL voltage.

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