Comments on: Lightweight USB Host. Part 4 – The code. http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository A Solder Joint Thu, 17 May 2012 05:09:08 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: oleg http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3694 oleg Wed, 06 Apr 2011 15:14:03 +0000 http://www.circuitsathome.com/?p=690#comment-3694 Only CPU can set/clear LOWSPEED. Only CPU can set/clear LOWSPEED.

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3689 Jason Wed, 06 Apr 2011 08:48:08 +0000 http://www.circuitsathome.com/?p=690#comment-3689 so does that mean the LOWSPEED bit also update itself when the device is connected? like when a lowspeed device is connected the lowspeed bit will go high in the rMODE and when it is use to check with the bmLOWSPEED and rMODE , it is use to determine if its high or low speed according to the KSTATUS or JSTATUS right? so does that mean the LOWSPEED bit also update itself when the device is connected? like when a lowspeed device is connected the lowspeed bit will go high in the rMODE and when it is use to check with the bmLOWSPEED and rMODE , it is use to determine if its high or low speed according to the KSTATUS or JSTATUS right?

]]> By: oleg http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3681 oleg Wed, 06 Apr 2011 01:52:40 +0000 http://www.circuitsathome.com/?p=690#comment-3681 Low-speed device has one data line pulled up by a resistor an full-speed device has other data line pulled up by the resistor. Host controller has both data lines pulled down by larger resistors. It reads data lines and determines speed by whatever data line is high at the moment. The J, K are updated automatically after device connect. If you start host controller with device already attached, you need to set SAMPLEBUS, wait for it to reset and then read JSTATUS,KSTATUS. Relation between JSTATUS,KSTATUS and speed depend on state of LOWSPEED - take a look at busprobe() function in USB Host code to see how it works. Low-speed device has one data line pulled up by a resistor an full-speed device has other data line pulled up by the resistor. Host controller has both data lines pulled down by larger resistors. It reads data lines and determines speed by whatever data line is high at the moment. The J, K are updated automatically after device connect. If you start host controller with device already attached, you need to set SAMPLEBUS, wait for it to reset and then read JSTATUS,KSTATUS. Relation between JSTATUS,KSTATUS and speed depend on state of LOWSPEED – take a look at busprobe() function in USB Host code to see how it works.

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3672 Jason Tue, 05 Apr 2011 10:01:45 +0000 http://www.circuitsathome.com/?p=690#comment-3672 Hi oleg, if you dont mind helping me out, could you explain to me how the KSTATUS and JSTATUS bit determine if the device connected is high speed or low speed? and what does it have to do with the LOWSPEED bit? does the LOWSPEED updates itself when a device is connected? i am having trouble finding out the flow of how the device is detected. thanks. Here is my concept of how it works, pls correct me if im wrong. B4 a device is detected, the cpu set the HOST =1 , DPPULLDN = 1 and DMPULLDN = 1 to make the logic in the D+ and D- low. then when a device is plug in, depend on the device(if its high speed or low speed) it will make the D+ or D- to have voltage through it. so when a device is detected, the cpu ( my 18f4550) reads the rHRSL register and examines the KSTATUS and JSTATUS bit when SAMPLEBUS = 1 ( does it automatic update the kstatus and jstatus itself ? ). So if it is a high speed device, the Kstatus should be high right according to the datasheet? and so in the end its all about checking on the kstatus and jstatus. my main question is really on how the kstatus and jstatus update itself and when D+ is high voltage and D- is low voltage, does that mean it updates the kstatus ? sorry if some question could be the same, i just have to be certain. thanks !! pls reply as soon as possible. Hi oleg, if you dont mind helping me out, could you explain to me how the KSTATUS and JSTATUS bit determine if the device connected is high speed or low speed? and what does it have to do with the LOWSPEED bit? does the LOWSPEED updates itself when a device is connected? i am having trouble finding out the flow of how the device is detected. thanks.

Here is my concept of how it works, pls correct me if im wrong.
B4 a device is detected, the cpu set the HOST =1 , DPPULLDN = 1 and DMPULLDN = 1 to make the logic in the D+ and D- low. then when a device is plug in, depend on the device(if its high speed or low speed) it will make the D+ or D- to have voltage through it. so when a device is detected, the cpu ( my 18f4550) reads the rHRSL register and examines the KSTATUS and JSTATUS bit when SAMPLEBUS = 1 ( does it automatic update the kstatus and jstatus itself ? ). So if it is a high speed device, the Kstatus should be high right according to the datasheet? and so in the end its all about checking on the kstatus and jstatus.

my main question is really on how the kstatus and jstatus update itself and when D+ is high voltage and D- is low voltage, does that mean it updates the kstatus ? sorry if some question could be the same, i just have to be certain. thanks !! pls reply as soon as possible.

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3466 Jason Sat, 19 Mar 2011 05:47:29 +0000 http://www.circuitsathome.com/?p=690#comment-3466 Oh . I dont think that is possible because i am already in the midst of my project and its due in 3 weeks, i just got to be able to detect the pendrive from my usb port. So if you can help me to achieve that with just the required code i would really appreciate that :). The thing is that after looking at some examples all over the internet, i just cant find the right coding except on this page since u were using a 18F PIC so i thought maybe if u could help me point out just the required Void or header file then i could achieve my goal d . much help appreciated! thanks! Oh . I dont think that is possible because i am already in the midst of my project and its due in 3 weeks, i just got to be able to detect the pendrive from my usb port. So if you can help me to achieve that with just the required code i would really appreciate that :) . The thing is that after looking at some examples all over the internet, i just cant find the right coding except on this page since u were using a 18F PIC so i thought maybe if u could help me point out just the required Void or header file then i could achieve my goal d . much help appreciated! thanks!

]]> By: oleg http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3454 oleg Fri, 18 Mar 2011 14:26:05 +0000 http://www.circuitsathome.com/?p=690#comment-3454 I don't think Arduino code can be easily ported to PIC. I was suggesting to switch your development to Arduino platform. I don’t think Arduino code can be easily ported to PIC. I was suggesting to switch your development to Arduino platform.

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3447 Jason Fri, 18 Mar 2011 07:36:19 +0000 http://www.circuitsathome.com/?p=690#comment-3447 The thing is that i dont know how to configure my PIC to arduino code. It is already complex trying to understand the basic stuff. Do you know how to configure the code that you wrote in arduino to support what i am trying to achieve? Thanks The thing is that i dont know how to configure my PIC to arduino code. It is already complex trying to understand the basic stuff. Do you know how to configure the code that you wrote in arduino to support what i am trying to achieve? Thanks

]]> By: oleg http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3427 oleg Thu, 17 Mar 2011 02:54:08 +0000 http://www.circuitsathome.com/?p=690#comment-3427 See my comment above. This code is unfinished and unsupported. Don't use it, go with Arduino. See my comment above. This code is unfinished and unsupported. Don’t use it, go with Arduino.

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3424 Jason Thu, 17 Mar 2011 02:38:17 +0000 http://www.circuitsathome.com/?p=690#comment-3424 Oh and im using PIC18f4550. thanks :) Oh and im using PIC18f4550. thanks :)

]]> By: Jason http://www.circuitsathome.com/mcu/lightweight-usb-host-part-4-the-code-repository/comment-page-1#comment-3423 Jason Thu, 17 Mar 2011 02:29:18 +0000 http://www.circuitsathome.com/?p=690#comment-3423 Hi oleg, very informative codes and description ! Here is my situation, i am in my final year project where i want to be able to detect a pendrive and then show the file's name in the pendrive on the 4x20 LCD screen that i have. For now i just want to be able to detect the pendrive and the LCD will display " pendrive found". Which of the codes do i have to use only? Like the max3421e.c , max3421e.h , project_config.h . what else do i need from the code? starting out slow first so i can understand whats going on properly. Thanks!! much help appreciated :) Hi oleg, very informative codes and description !
Here is my situation, i am in my final year project where i want to be able to detect a pendrive and then show the file’s name in the pendrive on the 4×20 LCD screen that i have. For now i just want to be able to detect the pendrive and the LCD will display ” pendrive found”. Which of the codes do i have to use only? Like the max3421e.c , max3421e.h , project_config.h . what else do i need from the code? starting out slow first so i can understand whats going on properly. Thanks!! much help appreciated :)

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