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Merge pull request #116 from triffid/feature/NXP_improved-baudrate-calculation 

NXP targets: Improved baudrate calculation function
pull/133/head
Bogdan Marinescu 2013-12-02 01:47:45 -08:00
parent 2897644e1b a249e39826
commit 43e49e5295
7 changed files with 287 additions and 112 deletions
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57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11UXX/serial_api.c
View File

@ -124,22 +124,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/serial_api.c
View File

@ -121,22 +121,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c
View File

@ -124,22 +124,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC176X/serial_api.c
View File

@ -157,22 +157,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC23XX/serial_api.c
View File

@ -156,22 +156,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC408X/serial_api.c
View File

@ -147,22 +147,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}

57
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC43XX/serial_api.c
View File

@ -130,22 +130,47 @@ void serial_baud(serial_t *obj, int baudrate) {
uint16_t dlv;
uint8_t mv, dav;
if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
float err_best = (float) baudrate;
uint16_t dlmax = DL;
for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
for ( mv = 1; mv <= 15; mv++) {
for ( dav = 1; dav < mv; dav++) {
float ratio = 1.0f + ((float) dav / (float) mv);
float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
if (err < err_best) {
DL = dlv;
DivAddVal = dav;
MulVal = mv;
err_best = err;
if (err < 0.001f) {
hit = 1;
}
int err_best = baudrate, b;
for (mv = 1; mv < 16 && !hit; mv++)
{
for (dav = 0; dav < mv; dav++)
{
// baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
// solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
// mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
// for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
// note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
else // 2 bits headroom, use more precision
dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
// datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
if (dlv == 0)
dlv = 1;
// datasheet says if dav > 0 then DL must be >= 2
if ((dav > 0) && (dlv < 2))
dlv = 2;
// integer rearrangement of the baudrate equation (with rounding)
b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
// check to see how we went
b = abs(b - baudrate);
if (b < err_best)
{
err_best = b;
DL = dlv;
MulVal = mv;
DivAddVal = dav;
if (b == baudrate)
{
hit = 1;
break;
}
}
}