MCP433X datasheet(57/88 Pages) MICROCHIP

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DS22242A-page 57

MCP433X/435X

7.6

Read Data

Normal and High Voltage

The Read command is a 16-bit command. The format

of the command is shown in Figure 7-4.

The first 6 bits of the Read command determine the

address and the command. The 7th clock will output

the CMDERR bit on the SDO pin. The remaining

9-clocks the device will transmit the 9 data bits (D8:D0)

of the specified address (AD3:AD0).

Figure 7-4 shows the SDI and SDO information for a

Read command.

7.6.1

SINGLE READ

The read operation requires that the CS pin be in the

active state (VILor VIHH). Typically, the CS pin will be in

the inactive state (VIH) and is driven to the active state

(VILor VIHH). The 16-bit Read command (command

byte and data byte) is then clocked in on the SCK and

SDI pins. The SDO pin starts driving data on the 7th bit

(CMDERR bit) and the addressed data comes out on

the 8th through 16th clocks. Figure 6-2 through

Figure 6-3 show possible waveforms for a single read.

FIGURE 7-4:

Read Command – SDI and SDO States.

XXXXXXXXXX

11111 D

Valid Address/Command combination

1111110000000000 Attempted Memory Read of Reserved

Memory location

COMMAND BYTE

DATA BYTE

SDI

SDO

READ DATA

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