Product Description

The Memory Adaptor is a single width CAMAC module which connects modules fitted with a private data highway to the Hytec 128K word CMOS Memory. It can be used to transfer data from ADCs or scalers into the memory module in list mode or to address the memory and perform a memory increment operation in histogramming mode.

The memory module may be accessed from the Dataway for the purposes of reading and writing the contents of the memory and also to perform a histogramming function. The Adaptor is equipped with two 40 way male header connectors to provide connection to:–

• ADC Private Data Highway.
• Memory Bus.

Up to 16 Memory modules may be connected on the Memory Bus to provide a total complement of 2M words. The module is equipped with front–panel mounted Lemo connectors, ’Request’ and ’Grant’ signal to allow connected ADCs to make requests for use of the Memory Bus. ADC priority is arranged on a geographical basis; those nearest to the Adaptor having highest priority. If an ADC does not make a bus request is passes the Grant signal onto the next ADC. The address register can be allocated for Dataway access, or for access via the ADC Private Data Highway when using list mode transfers. Arbitration of access of the memory is automatically carried out by the module on a ”first come first served” basis when memory increment cycles are executed on the Private Data Highway and the module is being accessed from the Dataway. If a CAMAC Write or Read operation is attempted when the module is receiving an ADC Request then the CAMAC operation is suppressed and Q Response is not generated. If an ADC makes a request for a transfer then Grant will not be generated until after the CAMAC operation has been completed.

Power Requirements

+6V at 1A from the mandatory Dataway supply.

Operating Temperature Range

0 deg. C to + 45 deg. C ambient.

Front Panel Lemo Connectors Request

Negative going TTL level or pulse which requests access to the memory. If a level is used this must be removed within 100 nanoseconds of the receipt of Grant.

Grant Details

Negative going TTL level which is generated by the adaptor module in response to a Request. The first unit to receive the Grant signal is given access to the memory and does so by gating its data onto the Data Highway. If a module receives Grant and is not generating Request it retransmits Grant on its Grant Out connector. Thus Grant is propagated along the Grant In/Grant Out chain until it is received by a unit which is generating a Request. When Grant is removed, the data must also be removed from the Highway. If the requesting unit generates Minc together with its data then this signals to the Adaptor module that a histogramming operation must be performed instead of an ordinary transfer to memory.

Printed Circuit Board Switches

SW1–SW4 Set the size of memory to be addressed in multiples of 128K words up to a maximum of 2M words.