Intelligent Motion Systems Motion Detector Using User-Defined SPI, SPI Timing Notes

SECTION 2.7

Using User-Defined SPI

The MForce can be configured and operated through the end-user's SPI interface without using the IMS SPI Mo- tor Interface software and optional parameter setup cable.

An example of when this might be used is in cases where the machine design requires parameter settings to be changed on-the-fly by a software program or multiple system Microstepping MForce PowerDrive units parameter states being written/read.

SPI Timing Notes

1.MSb (Most Significant bit) first and MSB (Most Significant Byte) first.

2.8 bit bytes.

3.25 kHz SPI Clock (SCK).

4.Data In (MOSI) on rising clock.

5.Data Out (MISO) on falling clock.

Figure 2.7.1: SPI Timing

Check Sum Calculation for SPI

The values in the example below are 8-bit binary hexadecimal conversions for the following SPI parameters:

MRC=25%, MHC=5%, MSEL=256, HCDT=500 mSec, WARNTEMP=80.

The Check Sum is calculated as follows: (Hex) 80+19+05+00+00+01+F4+50

Sum = E3	1110 0011
1’s complement = 1C	0001 1100	(Invert)
2’s complement = 1D	0001 1101	(Add 1)

Send the check sum value of 1D

Note: 80 is always the first command on a write.

Note: Once a write is performed, a read needs to be performed to see if there is a fault. The fault is the last byte of the read.

Part 2: Interfacing and Configuring 41