MODEM CONTROLLER 1 -CONT.

T.O. 31S5-4-308-1

TM 11-5805-663-14-13

NAVELEX 0967-464-0010

Adapter to perform read (to INFIBUS) or write

enables the Mag Tape Controller to transfer

(from INFIBUS) operations. When the Mag

a group of data bytes (called blocks) =

Tape Controller is ready to begin transfers,

These blocks are transferred directly to the

it notifies the Block Transfer Adapter via the

Core Memory during the loading of an oper-

BTA control lines, BTA1-N through BTA4-N.

ating program, to or from the RMR function

This control word also causes the Block

during rapid memory reload, or to the TTY

Transfer Adapter to operate as a master.

function after the utility print program has

been loaded.

5-84. The Block Transfer Adapter now gen-

erates a DDT, as explained previously,

5 - 8 2 . To transfer a block of data from the

which places the starting address on the

Formatter function, the Formatter causes

INFIBUS address lines, AB00-N through

the Mag Tape Controller to generate a level

AB15-N. If a write operation is to be per-

3 interrupt. To transfer a block of data to

formed RITE-N is generated and the data

the Formatter function the stored software

from the INFIBUS data lines is loaded into

program determines when data is to be

the Mag Tape Controller. When the Mag

transferred. In both of these cases, the

Tape Controller accepts the data, it gener-

Mag Tape Controller and Block Transfer

ates DONE-N which frees the INFIBUS.

Adapter status registers (address F8C0 16)

This data is clocked through the Mag Tape

are written into which clears both functions.

Controller to the Formatter. At the same

When both functions are cleared the Mag

time, the Block Transfer Adapter block

Tape Controller generates DONE-N which

length register is decremented by one and

frees the INFIBUS. Then the CPU addresses

the address register is incremented by one.

the Mag Tape Controller and Block Trans-

After the data is clocked through the Mag

fer Adapter control registers (address

Tape Controller, it notifies the Block Trans-

F8C6 16) and loads a control word from the

fer Adapter, via the BTA control lines, that

INFIBUS data lines, DB00-N through

it is ready to perform another transfer and

DB15-N, into the control registers. This

the sequence is repeated (except address is

control word idles the Block Transfer Adapter

increased by one) until the block length

and enables the Mag Tape Controller to

transfer data. The CPU new initializes the

Mag Tape Unit via the Mag Tape Controller

5 - 8 5 . If a read operation is to be performed,

and Formatter functions. The CPU then gen-

erates a second control word that idles the

RITE-N is not generated and the Mag Tape

Mag Tape Controller and enables the Block

Controller places the data on the INFIBUS

data lines. The Mag Tape Controller then

Transfer Adapter. The CPU now writes the

generates DONE-N which frees the INFIBUS.

block length (number of blocks to be

At the same time the block length register

transferred) into the Block Transfer Adapter

block length register (address F8C4 16).

decrements by one and the address register

When the block length is loaded in the

increments by one. The Mag Tape Con-

block length register the Block Transfer

troller notifies the Block Transfer Adapter

Adapter generates DONE-N which frees the

that it is ready to perform another data

INFIBUS. The CPU then loads one of the

transfer and the sequence is repeated

following addresses into the Block Transfer

(except address is increased by one) until

Adapter address register (address F8C2 16):

the block length register is at zero.

start address (if the data is to be read from

or written into Core Memory), RMR address

5 - 8 6 . When the block length register

(if the data is to be read from or written into

reaches zero, all Mag Tape Controller and

the RMR function), or the TTY function

Block Transfer Adapter operations cease.

address (utility print program).

Also, the Mag Tape Controller generates a

level 3 interrupt which notifies the CPU

5 - 8 3 . The CPU now loads a control word

that the block transfer is complete. The

into the Block Transfer Adapter and Mag

CPU then reinitializes the Mag Tape Con-

Tape Controller control register that enables

troller and Block Transfer Adapter with a new

the Mag Tape Controller and Block Transfer

block length and, starting address. This

5-13