Analog Integrated Circuit Device Data

Freescale Semiconductor

19

33894

FUNCTIONAL DEVICE OPERATION

LOGIC COMMANDS AND REGISTERS

SOLDERING INFORMATION

The 33894 is packaged in a surface mount power package

intended to be soldered directly on the printed circuit board.

The 33894 was qualified in accordance with JEDEC

standards JESD22-A113-B and J-STD-020A. The

recommended reflow conditions are as follows:

• Convection: 235°C +5.0/-0°C

• Vapor Phase Reflow (VPR): 235°C +5.0/-0°C

• Infrared (IR)/Convection: 235°C +5.0/-0°C

The maximum peak temperature during the soldering

process should not exceed 240°C. The time at maximum

temperature should range from 10 s to 40 s maximum.

LOGIC COMMANDS AND REGISTERS

Figure 9. Single 16-Bit Word SPI Communication

SERIAL INPUT COMMUNICATION

SPI communication is accomplished using 16-bit

messages. A message is transmitted by the MCU starting

with the MSB D15 and ending with the LSB, D0 (Table 7).

Each incoming command message on the SI pin can be

interpreted using the following bit assignments: the MSB,

D15, is the watchdog bit. In some cases, output selection is

done with bits D12:D11. The next three bits, D10:D8, are

used to select the command register. The remaining five bits,

D4:D0, are used to configure and control the outputs and

their protection features.

Multiple messages can be transmitted in succession to

accommodate those applications where daisy chaining is

desirable, or to confirm transmitted data, as long as the

messages are all multiples of 16 bits. Any attempt made to

latch in a message that is not 16 bits will be ignored.

The 33894 has defined registers, which are used to

configure the device and to control the state of the outputs.

Table 8, page 20, summarizes the SI registers.

CS

CSB

SI

SCLK

SO

D15

D1

D2

D3

D4

D5

D6

D7

D8

D9

D14

D13

D12

D11

D10

OD12

D0

OD13

OD14

OD15

OD6

OD7

OD8

OD9

OD10

OD11

OD1

OD2

OD3

OD4

OD5

1.

RSTB is in a logic H state during the above operation.

2.

DO, D1, D2, ... , and D15 relate to the most recent ordered entry of program data into the LUX IC

3.

OD0, OD1, OD2, ..., and OD15 relate to the first 16 bits of ordered fault and status data out of the LUX IC

NOTES:

OD0

CS

device.

device.

1. RST is a logic [1] state during the above operation.

2. D15:D0 relate to the most recent ordered entry of data into the device.

3. OD15:OD0 relate to the first 16 bits of ordered fault and status data out of the device.

Notes

Table 7. SI Message Bit Assignment

Bit Sig

SI Msg Bit

Message Bit Description

MSB

D15

Watchdog in: toggled to satisfy watchdog

requirements.

D14

Not used.

D12

Register address bits used in some cases

for output selection.

D10

Register address bits.

D7

Not used.

D4

Used to configure the inputs, outputs, and

the device protection features and SO

status content.

LSB

D0

Used to configure the inputs, outputs, and

the device protection features and SO

status content.