Reply by rtstofer February 23, 20102010-02-23
--- In l..., Priyank Maiya wrote:
>
> Hi,
> Could anyone please help me with this.
>
> Thanks,
> Priyank

If you are using the DB9 connector (assuming it has one) then you are dealing with RS232 and that should talk to a PC quite well with a straight-through cable

Does your other gadget also use RS232? Does it also talk to a PC with a straight-through cable? If so, you need a null modem cable to make the connection.

All you really need to do is swap pins 2 & 3 from end to end so that Tx on one end connects to Rx on the other.

Your code looks fine.

Richard

An Engineer's Guide to the LPC2100 Series

Reply by Priyank Maiya February 23, 20102010-02-23
Hi,
Could anyone please help me with this.

Thanks,
Priyank

On Sun, Feb 21, 2010 at 10:39 PM, Priyank Maiya wrote:

> Hi,
> Thanks for the reply.
> But the board i have i.e lpc2138 has a clock of 60MHz. I confirmed this by
> the sample string, which i printed onto the hyperterminal via UART0. For
> 9600 baud, I had to give 390, which matched the pclk of 60 MHz. I was able
> to see the string printed on the hyperterminal.
>
> I was wondering, if i am missing something like, setting/initializing any
> register in the UART0. Or is it a must to use interrupts for receiving data
> from the RX pin.
>
> Regards,
> Priyank
> On Sun, Feb 21, 2010 at 7:44 PM, ro.rente wrote:
>
>> Hi
>> Maybe you have wrong set in clock section.
>> If you have pclk 15Mhz (60/4 Reset Value)then good sets is DLL5
>> DLM =0.Try to use this
>>
>> http://ics.nxp.com/support/documents/microcontrollers/xls/lpc2000.uart.baudrate.calculator.xls
>> If im wrong please correct.
>>
>> Regards
>> Tomek
>> --- In l... ,
>> "priyankvmaiya2" wrote:
>> >
>> > Hi,
>> > I have an external device(board) which gives data at the rate of 240
>> bytes per second. This data is sent at a baud rate of 4800 baud, 8 bits, 1
>> stop bit, and no parity.
>> > I need to collect this data into my lpc2138 board and print it to
>> hyperterminal via UART0
>> >
>> > To print some sample string from the lpc2138 board to the hyperterminal
>> via UART0, I had to set the baud rate to 9600 (i.e. without the external
>> device). This works.
>> >
>> > But when I change the baud rate to 4800, my board does not detect any
>> data from the external device. I have connected the external device to the
>> pin P0.1 which is RXD0 " Receiver input for UART0. i.e. The
>> UART0_LSR bit for Read Buffer Register is always 0 which means the register
>> is empty.
>>
>> > I am not using interrupt for this.
>> >
>> > Can anyone please tell me where I am going wrong.
>> > I have pasted my code snippet below.
>> >
>> > PINSEL0 = 0x5; // Enable RxD0 and TxD0
>> > UART0_LCR = 0x00000083; // 8 bits, no Parity, 1 Stop bit
>> > UART0_DLL = 0x0000000C; // 4800 Baud Rate @ 60MHz VPB Clock
>> > UART0_DLM = 0x00000003; // 4800 Baud Rate @ 60MHz VPB Clock
>> > UART0_LCR = 0x00000003; // DLAB = 0
>> > UART0_FCR = 0x00000007; // Enable and reset TX and RX FIFO.
>> >
>> > while(1)
>> > {
>> > recv_byte = getchar();
>> > dec2bin(recv_byte, binary);
>> > }
>> >
>> > int getchar (void)
>> > {
>> > while (!(UART0_LSR & 0x01)); // Does not execute beyond this point.
>> > return (UART0_RBR);
>> > }
>> >
>> >
>> >
>> > Thanks,
>> > Priyank
>> >
>>
>>
>>
Reply by Priyank Maiya February 22, 20102010-02-22
Hi,
Thanks for the reply.
But the board i have i.e lpc2138 has a clock of 60MHz. I confirmed this by
the sample string, which i printed onto the hyperterminal via UART0. For
9600 baud, I had to give 390, which matched the pclk of 60 MHz. I was able
to see the string printed on the hyperterminal.

I was wondering, if i am missing something like, setting/initializing any
register in the UART0. Or is it a must to use interrupts for receiving data
from the RX pin.

Regards,
Priyank

On Sun, Feb 21, 2010 at 7:44 PM, ro.rente wrote:

> Hi
> Maybe you have wrong set in clock section.
> If you have pclk 15Mhz (60/4 Reset Value)then good sets is DLL5
> DLM =0.Try to use this
>
> http://ics.nxp.com/support/documents/microcontrollers/xls/lpc2000.uart.baudrate.calculator.xls
> If im wrong please correct.
>
> Regards
> Tomek
> --- In l... ,
> "priyankvmaiya2" wrote:
> >
> > Hi,
> > I have an external device(board) which gives data at the rate of 240
> bytes per second. This data is sent at a baud rate of 4800 baud, 8 bits, 1
> stop bit, and no parity.
> > I need to collect this data into my lpc2138 board and print it to
> hyperterminal via UART0
> >
> > To print some sample string from the lpc2138 board to the hyperterminal
> via UART0, I had to set the baud rate to 9600 (i.e. without the external
> device). This works.
> >
> > But when I change the baud rate to 4800, my board does not detect any
> data from the external device. I have connected the external device to the
> pin P0.1 which is RXD0 " Receiver input for UART0. i.e. The
> UART0_LSR bit for Read Buffer Register is always 0 which means the register
> is empty.
>
> > I am not using interrupt for this.
> >
> > Can anyone please tell me where I am going wrong.
> > I have pasted my code snippet below.
> >
> > PINSEL0 = 0x5; // Enable RxD0 and TxD0
> > UART0_LCR = 0x00000083; // 8 bits, no Parity, 1 Stop bit
> > UART0_DLL = 0x0000000C; // 4800 Baud Rate @ 60MHz VPB Clock
> > UART0_DLM = 0x00000003; // 4800 Baud Rate @ 60MHz VPB Clock
> > UART0_LCR = 0x00000003; // DLAB = 0
> > UART0_FCR = 0x00000007; // Enable and reset TX and RX FIFO.
> >
> > while(1)
> > {
> > recv_byte = getchar();
> > dec2bin(recv_byte, binary);
> > }
> >
> > int getchar (void)
> > {
> > while (!(UART0_LSR & 0x01)); // Does not execute beyond this point.
> > return (UART0_RBR);
> > }
> >
> >
> >
> > Thanks,
> > Priyank
> >
>
Reply by "ro.rente" February 21, 20102010-02-21
Hi
Maybe you have wrong set in clock section.
If you have pclk 15Mhz (60/4 Reset Value)then good sets is DLL=195
DLM =0.Try to use this
http://ics.nxp.com/support/documents/microcontrollers/xls/lpc2000.uart.baudrate.calculator.xls
If im wrong please correct.

Regards
Tomek
--- In l..., "priyankvmaiya2" wrote:
>
> Hi,
> I have an external device(board) which gives data at the rate of 240 bytes per second. This data is sent at a baud rate of 4800 baud, 8 bits, 1 stop bit, and no parity.
> I need to collect this data into my lpc2138 board and print it to hyperterminal via UART0
>
> To print some sample string from the lpc2138 board to the hyperterminal via UART0, I had to set the baud rate to 9600 (i.e. without the external device). This works.
>
> But when I change the baud rate to 4800, my board does not detect any data from the external device. I have connected the external device to the pin P0.1 which is RXD0 " Receiver input for UART0. i.e. The UART0_LSR bit for Read Buffer Register is always 0 which means the register is empty.
> I am not using interrupt for this.
>
> Can anyone please tell me where I am going wrong.
> I have pasted my code snippet below.
>
> PINSEL0 = 0x5; // Enable RxD0 and TxD0
> UART0_LCR = 0x00000083; // 8 bits, no Parity, 1 Stop bit
> UART0_DLL = 0x0000000C; // 4800 Baud Rate @ 60MHz VPB Clock
> UART0_DLM = 0x00000003; // 4800 Baud Rate @ 60MHz VPB Clock
> UART0_LCR = 0x00000003; // DLAB = 0
> UART0_FCR = 0x00000007; // Enable and reset TX and RX FIFO.
>
> while(1)
> {
> recv_byte = getchar();
> dec2bin(recv_byte, binary);
> }
>
> int getchar (void)
> {
> while (!(UART0_LSR & 0x01)); // Does not execute beyond this point.
> return (UART0_RBR);
> }
>
>
>
> Thanks,
> Priyank
>

Reply by priyankvmaiya2 February 21, 20102010-02-21
Hi,
I have an external device(board) which gives data at the rate of 240 bytes per second. This data is sent at a baud rate of 4800 baud, 8 bits, 1 stop bit, and no parity.
I need to collect this data into my lpc2138 board and print it to hyperterminal via UART0

To print some sample string from the lpc2138 board to the hyperterminal via UART0, I had to set the baud rate to 9600 (i.e. without the external device). This works.

But when I change the baud rate to 4800, my board does not detect any data from the external device. I have connected the external device to the pin P0.1 which is RXD0 Receiver input for UART0. i.e. The UART0_LSR bit for Read Buffer Register is always 0 which means the register is empty.
I am not using interrupt for this.

Can anyone please tell me where I am going wrong.
I have pasted my code snippet below.

PINSEL0 = 0x5; // Enable RxD0 and TxD0
UART0_LCR = 0x00000083; // 8 bits, no Parity, 1 Stop bit
UART0_DLL = 0x0000000C; // 4800 Baud Rate @ 60MHz VPB Clock
UART0_DLM = 0x00000003; // 4800 Baud Rate @ 60MHz VPB Clock
UART0_LCR = 0x00000003; // DLAB = 0
UART0_FCR = 0x00000007; // Enable and reset TX and RX FIFO.

while(1)
{
recv_byte = getchar();
dec2bin(recv_byte, binary);
}

int getchar (void)
{
while (!(UART0_LSR & 0x01)); // Does not execute beyond this point.
return (UART0_RBR);
}

Thanks,
Priyank