Low level UART support

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@196 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 112 insertions, 1 deletions

diff --git a/nuttx/arch/arm/src/lpc214x/lpc214x_lowputc.S b/nuttx/arch/arm/src/lpc214x/lpc214x_lowputc.S
index 8096ed3e9..bd9a86d0b 100644
--- a/nuttx/arch/arm/src/lpc214x/lpc214x_lowputc.S
+++ b/nuttx/arch/arm/src/lpc214x/lpc214x_lowputc.S
@@ -40,11 +40,70 @@
 #include <nuttx/config.h>
 #include "up_internal.h"
 #include "up_arch.h"
+#include "lpc214x_uart.h"
 
 /**************************************************************************
  * Private Definitions
  **************************************************************************/
 
+#if defined(CONFIG_UART0_SERIAL_CONSOLE)
+#  define LPC214X_UART_BASE    LPC214X_UART0_BASE
+#  define LPC214X_UART_PINSEL  LPC214X_UART0_PINSEL
+#  define LPC214X_UART_PINMASK LPC214X_UART0_PINMASK
+#  define LPC214X_UART_BAUD    CONFIG_UART0_BAUD
+#  define LPC214X_UART_BITS    CONFIG_UART0_BITS
+#  define LPC214X_UART_PARITY  CONFIG_UART0_PARITY
+#  ifdef CONFIG_UART0_2STOP
+#    define LPC214X_UART_2STOP 1
+#  endif
+#elif defined(CONFIG_UART1_SERIAL_CONSOLE)
+#  define LPC214X_UART_BASE    LPC214X_UART1_BASE
+#  define LPC214X_UART_PINSEL  LPC214X_UART1_PINSEL
+#  define LPC214X_UART_PINMASK LPC214X_UART1_PINMASK
+#  define LPC214X_UART_BAUD    CONFIG_UART1_BAUD
+#  define LPC214X_UART_BITS    CONFIG_UART1_BITS
+#  define LPC214X_UART_PARITY  CONFIG_UART1_PARITY
+#  ifdef CONFIG_UART1_2STOP
+#    define LPC214X_UART_2STOP 1
+#  endif
+#else
+#  error "No CONFIG_UARTn_SERIAL_CONSOLE Setting"
+#endif
+
+#if LPC214X_UART_BITS == 5
+#  define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_5
+#elif LPC214X_UART_BITS == 6
+#  define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_6
+#elif LPC214X_UART_BITS == 7
+#  define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_7
+#elif LPC214X_UART_BITS == 8
+#  define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_8
+#else
+#  error "No CONFIG_UARTn_BITS Setting"
+#endif
+
+#if LPC214X_UART_PARITY == 0
+#  define LPC214X_LCR_PAR LPC214X_LCR_PAR_NONE
+#elif LPC214X_UART_PARITY == 1
+#  define LPC214X_LCR_PAR LPC214X_LCR_PAR_ODD
+#elif LPC214X_UART_PARITY == 2
+#  define LPC214X_LCR_PAR LPC214X_LCR_PAR_EVEN
+#elif LPC214X_UART_PARITY == 3
+#  define LPC214X_LCR_PAR LPC214X_LCR_PAR_MARK
+#elif LPC214X_UART_PARITY == 4
+#  define LPC214X_LCR_PAR LPC214X_LCR_PAR_SPACE
+#else
+#  error "No CONFIG_UARTn_PARITY Setting"
+#endif
+
+#ifdef LPC214X_UART_2STOP
+#  define LPC214X_LCR_STOP LPC214X_LCR_STOP_2
+#else
+#  define LPC214X_LCR_STOP LPC214X_LCR_STOP_1
+#endif
+
+#define LPC214X_LCR_VALUE (LPC214X_LCR_CHAR | LPC214X_LCR_PAR | LPC214X_LCR_STOP)
+
 /**************************************************************************
  * Private Types
  **************************************************************************/
@@ -83,9 +142,61 @@
 	.type	up_lowputc, function
 up_lowputc:
 	/* On entry, r0 holds the character to be printed */
-#warning "Not implemented"
+
+	ldr	r1, =LPC214X_UART_BASE
+	strb	r0, [r1, #LPC214X_THR_OFFSET]
+
+	/* Wait for the byte to be transferred */
+
+1:	ldr	r0, [r1, #LPC214X_LSR_OFFSET]
+	ands	r0, #LPC214X_LSR_TEMT  /* Transmitter empty */
+	beq	1b
 
 	/* And return */
 
 	mov     pc, lr
+	.size	up_lowputc, . - up_lowputc
+
+/* This performs basic initialization of the UART.  This can be called very
+ * early in initialization because it does not depend on having a stack.  It
+ * modifies r0-r2 and r14.
+ */
+
+	.text
+	.globl	up_lowsetup
+	.type	up_lowsetup, function
+up_lowsetup:
+	/* Configure PINSEL0 */
+
+	ldr	r0, =LPC214X_PINSEL0
+	ldr	r1, [r0]
+	ldr	r2, =LPC214X_UART_PINMASK
+	and	r1, r2
+	ldr	r2, =LPC214X_UART_PINSEL
+	orr	r1, r2
+	str	r1, [r0]
+
+	/* Configure parity, data bits, stop bits and set DLAB=1 */
+
+	ldr	r0, =LPC214X_UART0_BASE
+	mov	r1, #(LPC214X_LCR_VALUE | LPC214X_LCR_DLAB_ENABLE)
+	strb	r1, [r0, #LPC214X_LCR_OFFSET]
+
+	/* Set the BAUD divisor */
+
+	mov	r1, #(UART_BAUD(LPC214X_UART_BAUD) >> 8)
+	strb	r1, [r0, #LPC214X_DLM_OFFSET]
+
+	mov	r1, #(UART_BAUD(LPC214X_UART_BAUD) & 0xff)
+	strb	r1, [r0, #LPC214X_DLL_OFFSET]
+
+	/* Clear DLAB */
+	
+	mov	r1, #LPC214X_LCR_VALUE
+	strb	r1, [r0, #LPC214X_LCR_OFFSET]
+
+	/* And return */
+
+	mov	pc, lr
+	.size	up_lowsetup, . - up_lowsetup
 	.end