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HC11 TCS and RTS signal generation

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Jun 2, 2011
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Hi all, I have a project to develop a micro-controlling system based on motorola`s 68hc11A1.So far I`ve managed to complete everything except for the interface. I am to connect the mcu with a pc through USB FT232. On the USB`s pdf i saw that i have to connect the usb`s TxD to the MCU`s RxD and the usb`s RxD to the MCU`s TxD, I aslo need to control the transfer rate meaning connecting RTS and CTS, And here is my question i red that hc11 does not have RTS and CTS signals so I am to use 2 general purpose I/O for to generate them but I`m not sure wich registers/flags should I be checking for them is TDRE an TC flags from SCSR register or ...?

For generating RTS and CTS you do not need any register at all. By these HW signals you inform you are ready for communication and also opposite site do the same.
You must do by your FW. Just set or clear IO pin. Which one? any.

4 Request To Send

* Name: CA
* Direction: DTE -> DCE
* CCITT: 105

Enables transmission circuits. The DTE uses this signal when it wants to transmit to the DCE. This signal, in combination with the Clear To Send signal, coordinates data transmission between the DTE and the DCE.

A logic 0 on this line keeps the DCE in transmit mode. The DCE will receive data from the DTE and transmit it on to the communication link.

The Request To Send and Clear To Send signals relate to a half- duplex telephone line. A half duplex line is capable of carrying signals on both directions but only one at a time. When the DTE has data to send, it raises Request To Send, and then waits until the DCE changes from receive to transmit mode. This "On" to "Off" transition instructs the DCE to move to "transmit" mode, and when a transmission is possible, the DCE sets Clear To Send and transmission can begin.

On a full duplex line, like a hard-wired connection, where transmission and reception can occur simultaneously, the Clear To Send and Request To Send signals are held to a constant "On" level.

A "On" to "Off" transition on this line instructs the DCE to complete the transmission of data that is in progress, and to move to a "receive" (or "no transmission") mode.

5 Clear To Send

* Name: CB
* Direction: DTE <- DCE
* CCITT: 106

An answer signal to the DTE. When this signal is active, it tells the DTE that it can now start transmitting (on Transmitted Data line). When this signal is "On" and the Request To Send,Data Set Ready, and Data Terminal Ready are all "On", the DTE is assured that its data will be sent to the communications link. When "Off", it is an indication to the DTE that the DCE is not ready, and therefor data should not be sent.

When the Data Set Ready and Data Terminal Ready signals are not implemented, in a local connection which does not involve the telephone network, the Clear To Send and Request To Send signals are sufficient to control data transmission.

---------- Post added at 19:56 ---------- Previous post was at 19:51 ----------

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