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发表于 2014-10-31 17:21:45
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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。6 u+ t4 v9 d+ k: T/ o
*** DaVinci Core Type *** | |7 {) W1 |2 \, D- v
| | [ ] DaVinci 644x based system | |1 v. _, I* }/ C0 \
| | [ ] DaVinci 355 based system | |8 R/ v- @) L6 o" y" r" I' E
| | [ ] DaVinci 646x based system | |* D) Z* ^) H3 ?4 Z
| | [ ] DA830/OMAP-L137/AM17x based system | |* u2 y7 | f1 F8 K, I" [
| | [*] DA850/OMAP-L138/AM18x based system | |% z+ t% G9 t" ?4 w
| | [ ] Enable UART1 flow control | |5 I9 x: C6 u$ E6 s5 s0 d
| | [ ] Enable UART0 RS485 funcation | |* X7 O, E2 ?4 B1 N5 G
| | [*] Enable UART1 RS485 funcation 2 x+ ^9 B- ?/ ~' |; e
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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;1 w% z4 i5 ~- h7 N2 ^+ Y0 M7 @! T
void serial8250_tx_chars(struct uart_8250_port *up)
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}
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d) t; C9 ]# Y+#if 1
3 n9 ]+ Z7 e% n- i+ /* The funcation with RS485 flow control */* ]2 Q; E5 p* u7 E9 [+ a
+ if (up->port.private_data) {: o0 L8 i7 t" J# `+ o! e, \- A
+ struct serial8250_flow_ctrl *flow_ctrl_p;
' r, s' `; a- n* {0 }+ flow_ctrl_p = up->port.private_data;
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2 u, b4 i; D8 [0 `2 V+ if (flow_ctrl_p->gpio) {5 Y1 ^0 K' k) e0 Y* o7 e; X2 i
+ gpio_set_value(flow_ctrl_p->gpio, 1);
& F5 D8 x4 W! l+ ndelay(50); /* Propagation delay >= 50ns */8 m+ f6 ~; o/ a0 `
+ }
" ~$ ^5 n6 D5 V+ }
4 A6 {5 f) U3 N+#endif1 B) }6 l0 N5 t9 }4 _5 X
希望对您有帮助。
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