Operation

MC3PHAC Monolithic Intelligent Motor Controller, Rev. 2

Freescale Semiconductor

21

Figure 13. MC3PHAC Configuration for Using a PC as a Master

PC Master Software Operation with the MC3PHAC

When power is first applied to the MC3PHAC, or if a logic low level is applied to the RESET pin, the

MC3PHAC enters PC master software mode if the VBOOST_MODE pin is low during the initialization

phase. The MC3PHAC recognizes a subset of the PC master software command set, which is listed in

Table 5.

With the READVARx commands, the addresses are checked for validity, and the command is executed

only if the address is within proper limits. In general, a read command with an address value below $0060

or above $EE03 will not execute properly, but instead will return an invalid operation response. An

Table 5. Recognized PC Host Software Commands

Command

Description

GETINFOBRIEF

MC3PHAC responds with brief summary of hardware setup and link configuration

information

READVAR8

MC3PHAC reads an 8-bit variable at a specified address and responds with its value

READVAR16

MC3PHAC reads a 16-bit variable at a specified address and responds with its value

READVAR32

MC3PHAC reads a 32-bit variable at a specified address and responds with its value

WRITEVAR8

MC3PHAC writes an 8-bit variable at a specified address

WRITEVAR16

MC3PHAC writes a 16-bit variable at a specified address

Notes:

2. Use bypass capacitors placed close to the MC3PHAC.

3. Consult crystal/resonator manufacturer for component values.

22 pF

22 pF

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

FROM DIVIDED DC BUS

+5 V

10 k

Ω

RESET

0.1

µF

NOTE 2

+5 A

MC3PHAC

A

+ 5

NOTE 2

FROM SYSTEM FAULT

DETECTION CIRCUIT

TO RESISTIVE BRAKE DRIVER

RESET

OSC2

OSC1

PLLCAP

PWMPOL_BASEFREQ

PWM_U_TOP

PWM_U_BOT

PWM_V_TOP

PWM_V_BOT

PWM_W_TOP

PWM_W_BOT

DC_BUS

ACCEL

SPEED

MUX_IN

START

FWD

VBOOST_MODE

DT_FAULTOUT

RBRAKE

RETRY/TxD

PWMFREQ/RxD

FAULTIN

10 k

Ω

0.1

µF

NOTE 3

10 M

Ω

+5 V

10 k

Ω

+5 V

FAULT LED

560

Ω

DATA TO PC

DATA FROM PC

ISOLATED

OR NON-ISOLATED

RS232 INTERFACE

CONNECTION

TO HOST

NOTE 1