Simon Ford
Program to dump out dividers for a UART, after it being set up
Revision 0:9343a4c09e4d, committed 2010-10-13
- Comitter:
- simon
- Date:
- Wed Oct 13 10:43:43 2010 +0000
- Commit message:
Changed in this revision
| main.cpp | Show annotated file Show diff for this revision Revisions of this file |
| mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Wed Oct 13 10:43:43 2010 +0000
@@ -0,0 +1,28 @@
+#include "mbed.h"
+
+DigitalOut myled(LED1);
+
+Serial s(p9, p10);
+
+int main() {
+
+ // setup the baudrate to 4800
+ s.baud(4800);
+
+ // extract the resulting divider values that were setup
+
+ LPC_UART3->LCR |= (1 << 7); // set LCR[DLAB] to get access to dividers
+ int dlm = LPC_UART3->DLM;
+ int dll = LPC_UART3->DLL;
+ int div = LPC_UART3->FDR & 0xF;
+ int mul = LPC_UART3->FDR >> 4;
+ LPC_UART3->LCR &= ~(1 << 7); // clear LCR[DLAB]
+
+ int pclk = 96000000;
+
+ // from LPC1768 User Manual, 14.4.12 :
+ float baudrate = pclk / (16.0 * (float)(256 * dlm + dll) * (1.0 + ((float)div / (float)mul)));
+
+ printf("dlm = %d, dll = %d, div = %d, mul = %d\n", dlm, dll, div, mul);
+ printf("baudrate = %f\n", baudrate);
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Wed Oct 13 10:43:43 2010 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/e2ac27c8e93e