IBM 5150

Transmitter Holding Register
The Transmitter Holding Register contains the character to be serially
transmitted and is defined below:
Transmitter Holding Register (THR)
L----==; DATA BIT 1
r'"'\
3F8 DLAB=O WRITE ONLY
BIT 7 6 5
4 3 2
1 0
I I • DATA BIT 0
'---------1. DATA BIT 2
'--------- .. DATABIT3
'-------------1. DATA BIT 4
L--------------a DATA BIT 5
'--------------- ____ DATA BIT 6
L- _______________ ----I~ DATA BIT 7
Bit 0 is the least significant bit and is the first bit serially transmitted.
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