TM USB-232 Driver-free USB to asynchronous serial UART interface Summary 128-byte Rx buffer UART Engine USB Serial 128-byte Tx buffer USB-232 is a single chip USB-to-asynchronous serial Engine Data interface. It greatly simplifies the connection of 128-AuxibyteliaryTx buffer I/O electronic devices to personal computer. In addition to USB the standard handshaking lines, additional control lines Status Control Outputs Inputs have custom-defined functionality. Applications USB-232 uses the Human Interface Device (HID) USB profile. It does not require USB drivers and so is USB to RS232 / RS422 / RS485 converters immediately plug-and-play with present and future USB data transfer for consumer products Windows, Linux and Mac operating systems. USB industrial control USB-232 is firmware for the PIC18LF2450 and PIC18F14K50 microcontrollers. It is available pre- Firmware Factory USB Product Family programmed as a 28-pin DIL package (2450) and a 20 pin SSOP package (14K50). USB-232 asynchronous serial interface TEAleaf-USB security and authentication dongle Features expandIO-USB I/O expander Single chip solution USB-SPI synchronous serial interface True HID plug and play - No drivers required USB-I2C synchronous serial interface No Vendor ID / Product ID registration required USB-TakeOff managed power take-off, wakeup USB 2.0 compatible and charge controller Baud rates selectable from 110 to 460K USB-DAQ data logger No flow control, X-on / X-off, Hardware flow USB-FileSys USB embedded file system control (CTS / RTS) Half duplex RS232 possible without a level Competitive positioning converter The USB-232 strengths compared to competitors are: Seven or eight data bits Low price One or two stop bits No driver installation required Even, odd, mark, space or no parity bit. No virtual COM port used - software can locate 128-byte FIFO receive buffer HID devices directly (sample code provided) 128-byte FIFO transmit buffer No Vendor ID / Product ID registration costs 11 invertible auxiliary I/O pins configurable as: CTS, RTS, DTR, DSR, DCD and RI USB-232s main limitation is a maximum data transfer rate 480K baud. Additionally, it is not suitable for USB / Self power sense retrofitting to COM port legacy applications Configured indication Suspend indication Electrical Specifications Host application ready indication Table 1. Electrical Specifications All-Systems-Go indication Operating voltage (20 pin / 28 pin) 1.8V/2.7V5.5V Tx / Rx LED drivers Typical/max supply current, Vdd = 3.3V TBD RS485 Tx Enable Typical/max supply current, Vdd = 5.0 10mA / 21mA Operating Temperature -40C to +85C Low power, Buffer empty indication Refer to base microcontroller data sheet for further information Data send control Firmware Factory Ltd Digital, analog, interrupt I/O rd 2 Marshall St, 3 Floor Reset / Soft Detach London W1F 9BB, UK Product name, manufacturer name, serial sales firmwarefactory.com number, GUID, EEPROM and I/O settings support firmwarefactory.com configurable from USB interface, minimizing hardware development costs Few external components required Operating voltage 3.3V 5V 122-byte EEPROM p1 of 11 26-Aug-10 USB-232 HW143-19 www.firmwarefactory.comUSB bus power. Vusb should be connected, via a Basic Operation 470nF capacitor, to Vss. See for example C8 in figure 2. To the electronic system (device), USB-232 looks like a OSC1, OSC2 serial UART. To the PC (host), it looks like a Human OSC1 and OSC2 should be connected to a 12MHz Interface Device (HID) with which it may exchange parallel cut crystal circuit with 22pF capacitors. It may information using simple commands. be replaced with a 12MHz resonator with 0.25% total Using the HID USB profile means that no driver tolerance. installation is required and immediate compatibility is RxD, TxD assured on Windows, Linux and OS systems. Additionally, software can find the device automatically Active low serial data input and output. without needing to know which virtual COM port it is Vpp, PGC, PCD occupying. TEAclipper programming pins. Refer to the Delivery and Programming section for details. Note that the Vpp pin may be subject to voltages as high as 12V during programming. VIO pins The VIO pin functions can be reconfigured as detailed in the customization section. The default functions are shown in table 2. The pins can be configured as follows. No Function The pin is a digital input that has no effect. To minimize power consumption, it should be biased high or low. Pin Functions This setting is available on all VIOs. The pin functions are shown in table 2. The function of Reset the virtual I/O pins is reconfigurable, so their default settings are also shown. The output pins are in a tri- The pin is an active low reset input. Resetting the state condition until ~20s after power-on. device effectively implements the soft detach function. Table 2. Device Pinout This setting is available on VIO0 only. 2450 14K50 Name Description USB Power Sense DIL SSOP 1 4 VIO0 Virtual I/O / *Reset (in) If the device is capable of operating while not plugged Vpp TEAclipper Vpp into a USB port, a USB Power Sense input should be 5 5 VIO1 Virtual I/O / *DCD (in) provided. This pin should indicate that a voltage is 6 6 VIO2 Virtual I/O / *DSR (in) detected on the V+ pin of the USB connector. It is used 7 7 VIO3 Virtual I/O / *RI (in) to reduce power consumption by entering into a sleep 23 8 VIO4 Virtual I/O / *DTR (out) mode when the USB is not present, and also to ensure 24 9 VIO5 Virtual I/O / *Suspend (out) that the USB engine correctly initializes when the device 17 10 TxD Serial data (out) 11 11 VIO6 Virtual I/O / *RTS flow control (out) is plugged in. The UART is not operational during sleep. 18 12 RxD Serial data (in) This setting must be on VIO9 or VIO10. 12 13 VIO7 Virtual I/O / *All-Systems-Go (out) Self Power Sense 13 14 VIO8 Virtual I/O / *Buffer Empty (out) 22 15 VIO9 Virtual I/O / *CTS flow control (in) If the device is capable of operating while not plugged 21 16 VIO10 Virtual I/O / *Send (in) into a USB port, a Self Power Sense input may be 25 VIO11 Virtual I/O / *Tx Ind (out) provided. This pin should indicate when the device is 26 VIO12 Virtual I/O / *Rx Ind (out) not drawing power from the USB bus and can help the 14 17 Vusb USB supply filter PC manage its power budget. This setting is available 15 D- USB data - 18 on any VIO pin. 27 PGC TEAclipper PGC 16 D+ USB data+ Tx Indication 19 28 PGD TEAclipper PGD 8,19 20 Vss Power ground reference Output for connecting to a transmit indication LED. It 20 1 Vdd Power positive input turns on for approximately 100ms when data has been 9 3 OSC1 Oscillator output transmitted to the host. This setting is available on any 10 2 OSC2 Oscillator input VIO pin except VIO0. * = default configuration = active low Rx Indication The pin functions are described in detail below. Output for connecting to a receive indication LED. It turns on for approximately 100ms when data has been Vss, Vdd, Vusb received from the host. This setting is available on any Vss is the power supply ground reference. Vdd should VIO pin except VIO0. be connected to a regulated supply, for example the p2 of 11 26-Aug-10 USB-232 HW143-19 www.firmwarefactory.com