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Revised 3-25-94

This application note discloses the Serial Interface Protocol for the SIMCHECK line of products. The enclosed information is a partial disclosure but it should be sufficient for advanced user wishing to implement their own computer interface program. Please note that the PC Communication Package (p/n INN-8448-11) still must be purchased since it includes the Serial Interface Module.


SIMCHECK Serial Protocol is a proprietary information of INNOVENTIONS Inc. and it is covered by copyright, patent pending, and trade secret protection. Users are hereby granted the use of the enclosed information only in conjunction with INNOVENTIONS' SIMCHECK units. INNOVENTIONS Inc. reserve the right to incorporate any change in said protocol without prior notice.

Protocol Overview

The main design constraint of the Serial Protocol was to avoid task overhead on the SIMCHECK regular memory testing program, and therefore it is implemented with short communication streams (up to 4 characters) from the PC to SIMCHECK, which are then polled rather than used as interrupts. Communication from SIMCHECK to PC is task controlled by SIMCHECK and therefore may include longer lines.

The second design constraint of the Serial Protocol was to allow a complete graphical emulation of the SIMCHECK display. This feature include short real-time communication streams (e.g. {'d', 3, 3, < CR> } which controls the animation characters) which are evidently not required for your own functional interface. Therefore, this protocol disclosure does not specify this type of commands and your program should merely ignore unknown streams without loss of functionality.

The third design constraint of the Serial Protocol was to create a loose, non-time- critical communication between SIMCHECK and the PC in order to retain SIMCHECK full independence. Also, the Protocol will not corrupt the test even if communication is lost (or intentionally ignored) for some time during the test. You will find this feature to be very useful in simplifying your own interface program!

SIMCHECK setup mode is fairly enhanced (and also somewhat complicated) in the standard PC Communication Package. You should use this package for all your setup purposes (which are stored in the non-volatile memory of the Serial Interface package). This partial disclosure does not cover the setup portion of the Serial Protocol.

SERIAL INTERFACE PROTOCOL (partial disclosure)


The serial communication setup is 9600 Baud, 8 bits data, 1 stop bit, no parity.

PC to SIMCHECK commands

PC to SIMCHECK commands during real-time operation are one character streams which correspond to the four switches of SIMCHECK. User program should now the current SIMCHECK mode (see below) and thus can determine which command to send in accordance with the standard SIMCHECK test program (e.g. send '1' emulating F1 during Standby to start the test).

List of the real-time commands from the PC to SIMCHECK:

Send '0' to cause ESC

Send '1' to cause F1

Send '2' to cause F2

Send '3' to cause F3

Note: SIMCHECK overhead protection will disable the communication channel if you transmit more than 3 switch command within 0.3 seconds. If this occur, reset SIMCHECK (turn off and on again). Redesign your time delays between commands in your program.

SIMCHECK to PC messages

SIMCHECK to PC messages during actual test operation are limited to short four character streams of the following format:

'c',x,x,< CR> where c is an asscii (lower case) character code which identify the message type, x is an actual number (used as decimal or hexadecimal) which is repeated twice for verification and ,< CR> is the carriage return (13) character. Please note that x is treated as an actual number (e.g. 2), not a character!

During error detection and for size speed information, SIMCHECK transmit explicit string information stream of the following format:

'c',"explicit message string",< CR> where c is again an asscii character code which identify the message type.

IMPORTANT NOTE: All messages (short or long) from SIMCHECK to PC are terminated by < CR> . Sometime you may find two consecutive < CR> . Therefore, your program should simply read all SIMCHECK message into a (say 80 character) buffer which is later parsed based on the leading character code.

Partial list of SIMCHECK messages to the PC

(NOTE: Messages with codes not listed below should be ignored as they pertain to PC visual emulation of SIMCHECK).

String type messages:

't',"string",< CR> - Test time message. If length of string <=3 - only tenth of seconds shown.

'z',"string",< CR> - Size message.

's',"string",< CR> - Speed message.

'w',"string",< CR> - SIMCHECK display echo message.

'a',x,"string",< CR> - SIMCHECK partial display echo message. Character x indicates relative position on SIMCHECK display.

'g',"string",< CR> - Error string of the type "vvvFvvvv".

'u',"string",< CR> - Memory bank message.

'y',"string",< CR> - LOOP number (in AUTOLOOP), BIT NUMBER (in SINGLE BIT TEST).

Short messages streams:

'l',x,x,< CR> - Test Mode: x=0 STANDBY, x=10h BASIC TEST, x=1fh SHORT BASIC TEST, x=20h EXTENSIVE, x=30h SINGLE BIT, x=40h AUTOLOOP, x=ffh DIAGNOSTIC. Extensive test further have 21h, 22h, etc. for the subtests. Use to indicate a start of a test mode.

'v',x,x,< CR> - Voltage message. x='o' 1.4Volt, x='0' 6.5V, x='1' 5.5V, x='2' 5.0V, x='4' 4.5V, x='5' 4.0V, x='6' 3.85V, x='7' 3.6V,

'c',x,x,< CR> - Various commands that should be ignored except for x=4 means that next speed strings will show speed drift.

'x',x,x,< CR> - Test End markers, the number x corresponds to current test modes as in the list above for code 'l'. Use to indicate the end of test mode.

'm',x,x,< CR> - Memory Under Test type indicator: x='0' regular, x='1' PS/2, x='2' AST, x='3' JEDEC 40 pin module, x='5' Bank adapter, x='6' 40-BIT PORT.

'f',x,x,< CR> - x is the current Soft Error Counter.

'r',x,x,< CR> - x is the Relative Refresh Counter.

'k',x,x,< CR> - x is the Relative Spikes Counter.

'q',x,x,< CR> - x is the current bit's speed during SINGLE BIT test.


We recommend that if you plan to write you own interface, use a standard communication software package (e.g. ProComm Plus) to view the output from the SIMCHECK serial interface. Set it for CR-LF so that each line received from SIMCHECK is scrolled.

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