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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。: u' [' s0 g. o' D9 n: i
*** DaVinci Core Type *** | |; X( [% P2 a+ y3 U' y: `. E
| | [ ] DaVinci 644x based system | |. W, H9 W: q5 E1 k0 l- i# V2 g
| | [ ] DaVinci 355 based system | |. _7 |& }3 P* }- v. ^( p* C8 W6 p* h) n+ S
| | [ ] DaVinci 646x based system | |
) ]! Z; f: X+ n! V | | [ ] DA830/OMAP-L137/AM17x based system | |% m" t5 {) E% ?$ S4 J( D
| | [*] DA850/OMAP-L138/AM18x based system | |! G a0 s9 j1 W7 s! _
| | [ ] Enable UART1 flow control | |) U5 k& d3 H3 b& t% o& F
| | [ ] Enable UART0 RS485 funcation | |
7 p0 V% K0 Z# N' O& p: i | | [*] Enable UART1 RS485 funcation
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想了解详细的功能实现，也可以查看8250.c文件里面的；$ j, W2 S" |5 }% ?. U2 }% Q
void serial8250_tx_chars(struct uart_8250_port *up); G4 F$ C4 f1 Y8 V% w& p' f# [
return;( t! o( l9 B* O: h# @, N F
}
+ x. u# s4 v" C' Z2 a
% w/ `5 O9 a4 b1 h/ w0 R+#if 1
6 A6 j4 A7 W* l. q. o% R+ /* The funcation with RS485 flow control */
6 `5 B# A5 u! l$ A+ W0 M5 }- {1 W2 a+ if (up->port.private_data) {0 J( H! F B* r) X6 m
+ struct serial8250_flow_ctrl *flow_ctrl_p;+ k z5 G% Q4 t7 U+ ~
+ flow_ctrl_p = up->port.private_data; \3 X( u q a0 v4 v. U8 a
+$ }& ^) H3 s- |
+ if (flow_ctrl_p->gpio) {% B7 C8 c* h+ e# n" w
+ gpio_set_value(flow_ctrl_p->gpio, 1);
$ h' R$ n' n( @+ u) d, Y- ~" {+ ndelay(50); /* Propagation delay >= 50ns */
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+ }
1 d) W, W; v: J( B6 R+#endif
2 U+ v4 A+ X' K% X i( t希望对您有帮助。
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发表于 2014-10-31 17:01:26
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