allanonmage
I am looking at the published specs here:
http://www.ez-robot.com/Shop/AccessoriesDetails.aspx?prevCat=9&productNumber=40
Servos
Voltage
The servo compatibility is listed as "5V tolerant", but don't most servos run best at 6 - 7.2 volts? It was my understanding that 5V is under powering servos, if not almost so.
Amperage
Can the EZ-Bv4 handle the amperage draw of many servos operating at once? For example, with Arduinos, they say that more than 1 or 2 can/will cause a brown out, so they say use an external power source. I have seen shields that allow this electrically but still allow you to use the 3 wire connector on the tail end of the servo.
The EZ-B has a dedicated PSU and ports and looks to be capable for 24 PWM servos. Can it handle them all moving at once, or is there an upper limit?
Processors
No questions, mostly chastisement. You can't take two processors and add their megahertz together to get a bigger number. That's not how things work. You should list both of them separately all of the time. I see that you do this in some of your marketing literature, but not all. You should always list both processors and find a new gimick rather than "200MHz 32-Bit Processing". Especially because PICs aren't even 32 bits, let alone processors; they're 16 bit micro controllers.
check this out...
j
The EZ-B v4 boasts 200mhz of 32-bit Processors (ARM Cortex M3 & Microchip PIC32)
SO...I plugged those names in my trusty Google search engine.......
and Microchip says their PIC32 is indeed 32bit and 200Mhz:
Microchip PIC32
and Cortex also says their chip is 32bit:
ARM Cortex M3
I'm no hardware expert by any means, nor an EZ Robot employee, but some quick Google searches seem to show their specs are accurate.
EDIT: I see what you are talking about now:
(120 MHz 32-bit Cortex M3 ARM Processor & 80 MHz Microchip PIC32)
Without the exact chip it's hard to tell, but they do have a 200Mhz version. And it is 32-bit
You can pull 20amps through the ezb4 board (combined on all pins) before the main fuse blows
1) The voltage you are referring to is the Signal voltage - which is not the power voltage. That means you can provide +5 input into the signal wires of the micro controller. The power is a different wire. In order to power a servo, it will require 3 wires (power, gnd and signal). The signal will be 3.3 Output but can take a maximum of 5 volts input. I refer you to the datasheet here for a clearer understanding of the EZ-B specifications. Click HERE for Datasheet. The LEARN link at the top of the main menu of this website may help you a lot. Almost all ARM Micros are 3.3v IN and 3.3v OUT, which doesn't make it easy to connect to 5v sensors because they return a 5v signal. The STM32 ARM Micro we use is 5v tolerant for IN and 3.3v for OUT. The datasheet will tell you more. Please check the datasheet for more info on the EZ-B. Feel free to ask questions of what the specs mean
2) EZ-Robot focuses on robots, which require many servos - up to 24, in fact. Our robots from the Revolution line come in 3 flavors and use more than 1 servo each. Some use 16, some use 18 and some use less. Here is a link to our store page which has robots that you can see using more than one servo
3) Processors - i understand your concern but the wording is combing the two processor speeds because there are two processors which are each performing their own tasks. To clarify for you, it's 200 MHz _OF_ processing. This is because a single processor at 120mhz or a single processor at 80mhz cannot hand the full load of computational instructions. So, in order to perform the number of computational instructions per second required for the EZ-B, we either need a 220 MHz single processor or 200 MHz with two processors (one being 120 MHz and the other being 80 MHz).
I can expand on that further if you need more clarification? The amount of processing required is 200 MHz but split between two processors.
You may also ask why a single processor would require 220 MHz, where two processors only needs 200 MHz? That question can be answered if you have understanding of task/thread management. Because the processors are single core, there needs to be tasks handled by a threading model, which itself takes computational power.
The EZ-B does a lot in it's low MHz between both chips because we offload a lot to DMA and hardware peripherals. However, the Audio, Video, PWM, TCP/HTTP Server, DHCP, WiFi, etc is computationally heavy.
Hope that helps clarify