FILE: pub/miniboard/hobbytip/BOTBoard.txt ------------------------------ [Note: Marvin Green may be reached at marvin@agora.rain.com. -- fgm] Newsgroups: comp.robotics Subject: review of Marvin Green's "BOTBoard" for the 6811 Summary: Followup-To: Distribution: world Organization: MIT Media Laboratory Keywords: Greetings comp.robotics readers, Out of curiosity, I ordered a copy of Marvin Green's BOTBoard for the 6811, and I'd like to share my observations about the board and documentation with you all. The BOTBoard measures 2 x 3 inches. 2 x 2 of this is the 6811 area; there are four screw-mounting holes in the corners of this area. The remaining 1 x 3 inch area is a general-purpose .1" grid prototyping space. There are 17 x 9 holes for parts/connectors, and one each 1 x 9 holes for power and ground strips. The board is a good quality single-sided design. There is no solder mask. The 6811 area mounts a 52-pin 6811 in a PLCC socket. The crystal circuit assumes a 2-wire crystal with two impedance-matching capacitors and one resistor. There is a spot to mount Motorola's voltage-monitoring reset chip (the MC34064) and a small pushbutton reset switch. The rest of the board is connectors. The connector of choice is the .1" spacing male header. Since the design of connectors has a large influence on the usability of the board, here is a thorough run-down: * Power is provided via a three-pin header; the two outer pins are +5v and the inner pin is ground. There is no regulator on the board. * TTL-level serial is broken out to a 4x1 pin which provides power and ground in addition to TxD and RxD. There is no serial level converter on the board, but you can supply power via this connector to an off-board converter circuit. The documentation provides plans for such a circuit using a Maxim MAX233 chip, suggesting that the whole circuit can be mounted inside a DB-25 connector hood. [I believe the info sheet on the BOTBoard to be slightly misleading on this point. It mentions a "Powered RS232 Port connector", which suggests RS232 line levels.] There is a 10K resistor on the board which hooks TxD to +5v. This is good because the TxD pin needs a pullup resistor to work properly when the 6811 is in bootstrap download mode. Also, you can temporarily jumper the RxD and TxD pins together to get the inexpensive 'A1 version of the 6811 to boot out of its 512 bytes of internal EEPROM. * Each of the four Port A timer pins PA3-PA6 are broken out to 3x1 servo connectors, providing power, ground, and signal. The servo power may be jumpered to either board +5v power or an alternate power source. * 6811 Port C is broken out to a 5x2 pin header, one power and one ground pin provided. * Ports E, B, and the rest of A are arranged in a 13x2 header (hey--- that's an IDC connector standard!), providing four +5 lines and two ground lines. * The SPI (high-speed serial network) circuit is hooked up to a 4x1 connector (MOSI, MISO, SCK, and ground). The Slave Select line may be separately jumpered to +5 or ground. That's it for the connectors. The BOTBoard is advertised as being designed for robotics use, and there are a number of clever ideas in the connector layout. The powered serial port connector is a good compromise if you're not going to put the converter circuit on your main board (though it should be advertised more straighforwardly), and it allows you to easily boot 'A1 chips. Another strong feature are the four servo ports. In this regard, the board lives up to its promise of being "specifically designed for robotics applications" (though it is certainly not the first to do so). The other connectors are functional as well. Each provides power and ground and uses an IDC configuration standard so you can use these plugs and wires if you wish. The BOTBoard documentation covers the premise behind the board's design, a feature list, parts list with supplier info, a schematic, construction notes, optional features explanation, application notes, and a pointer to public domain Motorola software for the 6811. It's well-organized and has ample diagrams. The main documentation is eight pages long, but Marvin also included issues one through seven of his P.A.R.T.S publication (Portland [Oregon] Area RoboTics Society) in his mailing to me. Each of these is a double-sided page with various robotics ideas and application notes. Each is oriented to the hands-on, beginning robotics hacker and contains a number of circuit plans. Overall, I'm impressed with the BOTBoard. It's perfect for bare-minimum 6811 designs where you just want the 6811 and a little bit of custom circuitry. The BOTBoard is not in competition with the Mini Board. The Mini Board gives you a number of features that the BOTBoard doesn't: DC motor drivers, a RS-232 line converter, and the ability to connect individual sensor devices. On the side of the BOTBoard, you get a prototyping area, servo connectors, and IDC connector headers which are great for connecting to other PCBs. Connecting individual sensors to the BOTBoard would be a little annoying though. I recommend that anyone who wishes to prototype minimal 6811 designs to get their hands on a BOTBoard. The price is right, it does the job, and it does it well. -Fred Martin encl: A copy of the information previously posted to this group about the BOTBoard, including ordering information. || T h e B O T B o a r d || || || The BOTBoard is the only single chip microcomputer board specifically || designed for robotics applications. The BOTBoard uses the popular || 68HC11 microcontroller, and is easily programmed from your PC. || Engineered to be small, the BOTBoard is also powerful and flexible. || || Each BOTBoard contains a 2" X 2" processor area and a 1" X 2" || proto-typing area. The proto-typing area allows additional circuitry or || connectors that may be needed. || || Special BOTBoard Features: || || . Four R/C Servo Ports. || . Reset Switch and low voltage circuitry. || . Auto start jumper. || . 1" X 2" proto-typing area, with power bus strips. || . Easy to use Networking Port (SPI). With Master/Slave selection. || . Powered RS232 Port connector for serial communication. || . Pull up resistors on IRQ and XIRQ. || . All I/O pins on .100 grid headers. || . Single sided circuit board design. || . Uses either the MC68HC11 or MC68HC811 . || . Mounting holes that can be used for stacking. || . Power supply connector. || || Features of the 68HC11: || || . Low power, less than 20ma. || . 256 RAM and 512 EEPROM memory with 68HC11, More with 68HC811. || . Eight A/D converter. || . RS-232 and SPI serial Ports. || . Real time interrupt and COP circuits. || . Auto start EEPROM code. || . With 36 I/O pins. || . Timer subsystem with three input captures. || . Five output compares and input accumulator. || . Boot loader program in ROM. || || || The BOTBoard is a bare circuit board that was designed to give the most || amount of flexibility for the least cost. Each board costs only $5.95 || in singles or three BOTBoards for $15. Following the simple || instructions, you can assemble the BOTBoard in less than a half hour, || with a total cost of the BOTBoard and parts being about $20. || || With each order the BOTBoard comes with detailed parts list, ordering || information, schematics, building instructions, and application guide. || || BOTBoard = $5.95 each. || BOTBoard = $5.00 each for three. || Shipping = $1.25 plus .25 for each board. || || Marvin Green || 821 SW 14th || Troutdale, OR 97060 || (503) 666-5907 call evenings. || || If you want to get an idea of his board, I wrote an article for || Nuts And Volts magazine demonstrating the toner transfer system and my || CNC machine. The differnce is his new design contains a proto area and is || 2X3 inches. The proto area can be cut off. || If you're into 68HC11 stuff you will find this a great buy! || || -- || [] SEANEWS [] Seattle Public Access Usenet News + Mail [] +1 206 747 NEWS [] || dmauch@seanews.akita.com Date: Mon, 29 Nov 1993 13:43:59 +0800 From: cmcmanis@frstprsn.Eng.Sun.COM (Chuck McManis) Message-Id: <9311292143.AA09986@pepper.Eng.Sun.COM> To: robot-board@oberon.com, fredm@media.mit.edu Subject: Re: review of Marvin Green's "BOTBoard" for the 6811 X-Sun-Charset: US-ASCII Content-Length: 479 Saw one of these at the Homebrew Robotics Club meeting last wednesday too. It would have been nice if it had plated thru holes as well. I find the biggest problem with radio shack type perfboard is that the lack of plated thru holes and the small copper pads makes it nearly impossible to do anything but hold down the parts using the pads. Another thing you can do however is not plug in connectors to the port c/e port and instead run wires to the perf board area. --Chuck