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您好！tronlong提供的最新的linux3.3内核已经对uart0和uart1做了rs485功能的支持，uart2默认为启动串口。如何想使能uart0和uart1 rs485的功能，只需在menuconfig将485使能。
( e t- E8 {& b *** DaVinci Core Type *** | |% i4 e8 P6 ~6 r
| | [ ] DaVinci 644x based system | |5 o1 U V1 v. ~4 Z
| | [ ] DaVinci 355 based system | |+ X; R& M9 U% m7 U
| | [ ] DaVinci 646x based system | |
, G( x6 i7 G7 R# S) n9 G7 J | | [ ] DA830/OMAP-L137/AM17x based system | |% E) J' ~ y+ t: y# E, J
| | [*] DA850/OMAP-L138/AM18x based system | |
: |( T0 ?& K3 N _& t | | [ ] Enable UART1 flow control | |
8 f6 H- n5 ~8 {, W3 u: \' @ | | [ ] Enable UART0 RS485 funcation | |
3 |; f/ Y/ O; i0 A+ r1 K3 w | | [*] Enable UART1 RS485 funcation 5 T. V) Z2 O. p$ y3 P7 {7 }
% j( R0 R! v+ b; L4 [/ ]
想了解详细的功能实现，也可以查看8250.c文件里面的；
. ^6 z: n' ]( H5 Z: Z6 U' L9 Uvoid serial8250_tx_chars(struct uart_8250_port *up)
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+#if 1
, K0 L6 G- p- j8 h) Q7 h+ /* The funcation with RS485 flow control */: Y; B7 X# e% P" r# v% x& S# Z
+ if (up->port.private_data) {
! e# J" _6 q \+ struct serial8250_flow_ctrl *flow_ctrl_p;
7 u6 U; P+ L( j5 |+ b$ V+ flow_ctrl_p = up->port.private_data;
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+ if (flow_ctrl_p->gpio) {6 z/ @% _% q( @* @
+ gpio_set_value(flow_ctrl_p->gpio, 1);6 M( j, }0 c4 ~2 c. j: h( J* M
+ ndelay(50); /* Propagation delay >= 50ns */
9 ^# f8 X N" A F4 u+ }
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+#endif
: i. f. z/ c1 [0 Z8 F8 R0 @9 o希望对您有帮助。9 I. i7 e2 n& [8 ~! k; r* T4 k, \
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发表于 2014-10-31 17:01:26
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