Commands - Motorola MC68824 User Manual

SECTION 3
COMMANDS
The host processor controls the TBC and the modem through the command mechanism. This
II
command mechanism is composed of the command register (CR), the semaphore register (SR),
and the command parameter area (CPA) in the initialization table. The 8-bit, write only, command
register is used to write commands to the TBC. The 8-bit, read only, semaphore register is used
to notify the host that execution of either the RESET or LOAD INITIALIZATION TABLE FUNCTION
CODE commands have been completed. The actual completion of a command except for RESET,
and LOAD INITIALIZATION TABLE FUNCTION CODE is indicated by the TBC setting of the 'done
bit' in the command parameter area in the initialization table. Another indication of command
completion is the TBC command complete bit (TCC) in the interrupt status word 0 which, if enabled,
can generate an interrupt to the host. The TBC command set is divided into the following cate-
gories:
Initialization,
Set Operation Mode,
TX Data Frames,
Set/Read Value,
Test,
Notify TBC, and
Modem Control.
Table 3-1 shows the commands for each category, while Table 3-2 illustrates each command's
encodings.
Table 3-1. TBC Commands by Categories
INITIALIZATION TEST
LOAD INITIAL TABLE FUNCTION CODE INTERNAUEXTERNAL LOOPBACK MODE
INITIALIZE RECEIVER TEST
OFFLINE TRANSMITIER TEST
IDLE HOST INTERFACE TEST
RESET FULL DUPLEX LOOPBACK TEST
SET OPERATION MODE
NOTIFY TBC
SET MODE 1 CLEAR INTERRUPT STATUS
SET MODE 2 RESPONSE READY
SET MODE 3
SET/CLEAR IN_RING DESIRED
TX DATA FRAMES MODEM CONTROL
STOP
PHYSICAL
RESTART
END PHYSICAL
START
SET/READ VALUE
READ VALUE
SET FUNCTION CODE OF BUFFER DESCRIPTORS
SET FUNCTION CODE OF FRAME DESCRIPTORS
SET FUNCTION CODE OF RX AND TX DATA BUFFERS
SET PAD TIMER PRESET (PTP) REGISTER
SET ONE WORD
SET TWO WORDS
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