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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。5 y% ]( j& b/ b& ]; q0 H
*** DaVinci Core Type *** | | W9 X' k2 W* k% |: o! x
| | [ ] DaVinci 644x based system | |# U2 p; b2 ~0 X6 s- _/ k
| | [ ] DaVinci 355 based system | |1 N" W" g7 Y; Z: i# }
| | [ ] DaVinci 646x based system | |
1 l% L* J6 _7 E& g2 D | | [ ] DA830/OMAP-L137/AM17x based system | |
$ J. ~$ d1 w$ e/ A | | [*] DA850/OMAP-L138/AM18x based system | |8 |7 P1 }4 ]% ?3 `: Q; [+ e
| | [ ] Enable UART1 flow control | |( t2 [2 B# x, e8 l, p+ R8 _. P
| | [ ] Enable UART0 RS485 funcation | |
N& Z0 W- I7 ~# \/ A2 v5 _8 q | | [*] Enable UART1 RS485 funcation * m% t2 [7 V! W/ d) H
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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；
* y) R1 C3 m4 ?& M! s0 v8 Y) l s1 Fvoid serial8250_tx_chars(struct uart_8250_port *up)
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}
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+#if 1
# @ g; v9 c5 m; k+ /* The funcation with RS485 flow control */1 T8 z N/ J6 O1 C
+ if (up->port.private_data) {% T! T0 {' k2 ] [( V+ q1 r
+ struct serial8250_flow_ctrl *flow_ctrl_p;5 r7 x* \) }3 y/ ]- o9 |/ H* E
+ flow_ctrl_p = up->port.private_data;
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( }7 Y6 G, F3 t0 R+ if (flow_ctrl_p->gpio) {
" E8 B- h1 U0 c% ` H+ gpio_set_value(flow_ctrl_p->gpio, 1);
- `7 k$ z+ @. M+ ndelay(50); /* Propagation delay >= 50ns */
$ k# y i# }5 Z: \ k) @' F+ }
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+#endif
1 s& ]8 l+ ^% b& \3 b希望对您有帮助。
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发表于 2014-10-31 17:21:45