Service manual

Section I: Imagesetter

Diagnostics 3-11

3.2.3.16 OCP Micro-controller Test Descriptions

The following list describes the tests performed on the OCP micro-controller during

the boot sequence:

•

External ROM Checksum–

performs

a rotate and add checksum on the

entire FLASHROM. Bytes are added to a 16-bit sum, after the sum has

been rotated right one position. Bit 0 is rotated into bit 15. The resulting

checksum is compared to the checksum stored in ROM at location 0. The

ROM size is stored in location 2; 1=128K, 2=256K.

•

Display Controller Test–

writes and reads the cursor, which veriﬁes that

the data path to the controller is functioning correctly.

•

Display RAM Test–

perform a read/write test of the display RAM to verify

its integrity. Several data patterns write to the RAM. The contents of the

display RAM are read back and compared against the expected data pat-

tern. Any discrepancies report as an error.

3.2.4 Automatic Dial-out Feature

During the power-up boot sequence, the diagnostic ﬁrmware attempts to call out to

a remote ﬁeld service site in the event of an error. The number dialed is pre-stored

in the modem's conﬁguration proﬁle.

At the beginning of the boot sequence the ﬁrmware sends an attention command

(AT) to the modem and waits for a response. If the modem responds with an OK,

the dial-out feature enables. If there is no response, the dial-out feature disables.

No response could mean that either no modem is installed/powered on or the

modem is currently on-line and in data mode. The operator inhibits an automatic

dial-out by pressing the + icon on the control panel after encountering an error. If

the + icon is pressed within 10 seconds after the error is displayed, the boot

sequence resumes and tries to complete. The steps proceed as follows:

1. Modem Initialization

Before dialing out, the diagnostic ﬁrmware initializes the modem. The

ﬁrmware waits for an OK response from the modem before continuing. If

the response is not received within 4 seconds, the ﬁrmware sends the

string again. To break out of this loop, reset the system/modem.

ATE0V1X4&C0&D0S7=120