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libchip ns16550.c: Improve comment

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This commit is contained in:
Joel Sherrill
2013-07-09 11:15:57 -05:00
parent 155ea78d9f
commit 48a22edb4a
1 changed files with 4 additions and 1 deletions
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5
c/src/libchip/serial/ns16550.c
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@@ -501,10 +501,13 @@ int ns16550_set_attributes(
/* /*
* Set the baud rate * Set the baud rate
*
* NOTE: When the Divisor Latch Access Bit (DLAB) is set to 1,
* the transmit buffer and interrupt enable registers
* turn into the LSB and MSB divisor latch registers.
*/ */
(*setReg)(pNS16550, NS16550_LINE_CONTROL, SP_LINE_DLAB); (*setReg)(pNS16550, NS16550_LINE_CONTROL, SP_LINE_DLAB);
/* XXX are these registers right? */
(*setReg)(pNS16550, NS16550_TRANSMIT_BUFFER, ulBaudDivisor&0xff); (*setReg)(pNS16550, NS16550_TRANSMIT_BUFFER, ulBaudDivisor&0xff);
(*setReg)(pNS16550, NS16550_INTERRUPT_ENABLE, (ulBaudDivisor>>8)&0xff); (*setReg)(pNS16550, NS16550_INTERRUPT_ENABLE, (ulBaudDivisor>>8)&0xff);