A serial cradle
Description: This project is aimed at building a small circuit that fits into a standard USB Visor cradle and that adds RS-232 capabilities. Note that Handspring sells a serial cradle but if you have more time than money, do it yourself and you will have a 2 in 1 cradle! The Handspring Visor / Visor deluxe is usually shipped with a USB cradle but this fairly recent interface is not supported by old PCs or PCs running under Windows 3.x, Windows 95 or Windows NT4. In that case, HotSync can be done only via a RS-232 connection.
The project involves the design and implementation of a circuit that enables RS-232 communication capabilities for the Handspring Visor / Visor Deluxe devices, which are typically equipped with a USB cradle. The aim is to create a dual-function cradle that allows users to connect their devices to older PCs that lack USB support, specifically those running legacy operating systems such as Windows 3.x, Windows 95, or Windows NT4.
The circuit design will incorporate a microcontroller or dedicated USB-to-RS-232 converter IC, which will handle the protocol conversion between USB and RS-232 standards. The design should ensure that the voltage levels are appropriately shifted, as RS-232 operates at higher voltage levels compared to USB signaling.
Key components may include a MAX232 or similar level shifter to convert between the TTL levels used by the microcontroller and the RS-232 levels required for communication. The circuit should also include necessary capacitors for the MAX232 to function correctly and ensure stability in communication.
Additionally, the schematic should depict the connections for the USB interface, including the data lines (D+ and D-) and the power lines (VCC and GND), ensuring that the cradle can draw power from the USB connection. The RS-232 side of the circuit will include the DB9 connector, which is the standard connector for RS-232 serial communication, along with appropriate pin configurations for transmitting (TX) and receiving (RX) data.
The final design should be compact enough to fit within the dimensions of the standard USB Visor cradle, allowing for easy integration and use. Proper attention should be given to PCB layout to minimize interference and ensure reliable communication. This project not only provides a cost-effective solution for users with older PCs but also enhances the versatility of the Visor device by enabling it to interface with a wider range of systems.This project is aimed at building a small circuit that fits into a standard USB Visor cradle and that adds RS-232 capabilities. Note that Handspring sells a serial cradle but if you have more time than money, do it yourself and you will have a 2 in 1 cradle !
The Handspring Visor / Visor deluxe is usually shipped with a USB cradle but this fairly recent interface is not supported by old PCs or PCs running under Windows 3.x, Windows 95 or Windows NT4. In that case, HotSync can be done only via a RS-232 connecti
The project involves the design and implementation of a circuit that enables RS-232 communication capabilities for the Handspring Visor / Visor Deluxe devices, which are typically equipped with a USB cradle. The aim is to create a dual-function cradle that allows users to connect their devices to older PCs that lack USB support, specifically those running legacy operating systems such as Windows 3.x, Windows 95, or Windows NT4.
The circuit design will incorporate a microcontroller or dedicated USB-to-RS-232 converter IC, which will handle the protocol conversion between USB and RS-232 standards. The design should ensure that the voltage levels are appropriately shifted, as RS-232 operates at higher voltage levels compared to USB signaling.
Key components may include a MAX232 or similar level shifter to convert between the TTL levels used by the microcontroller and the RS-232 levels required for communication. The circuit should also include necessary capacitors for the MAX232 to function correctly and ensure stability in communication.
Additionally, the schematic should depict the connections for the USB interface, including the data lines (D+ and D-) and the power lines (VCC and GND), ensuring that the cradle can draw power from the USB connection. The RS-232 side of the circuit will include the DB9 connector, which is the standard connector for RS-232 serial communication, along with appropriate pin configurations for transmitting (TX) and receiving (RX) data.
The final design should be compact enough to fit within the dimensions of the standard USB Visor cradle, allowing for easy integration and use. Proper attention should be given to PCB layout to minimize interference and ensure reliable communication. This project not only provides a cost-effective solution for users with older PCs but also enhances the versatility of the Visor device by enabling it to interface with a wider range of systems.This project is aimed at building a small circuit that fits into a standard USB Visor cradle and that adds RS-232 capabilities. Note that Handspring sells a serial cradle but if you have more time than money, do it yourself and you will have a 2 in 1 cradle !
The Handspring Visor / Visor deluxe is usually shipped with a USB cradle but this fairly recent interface is not supported by old PCs or PCs running under Windows 3.x, Windows 95 or Windows NT4. In that case, HotSync can be done only via a RS-232 connecti
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