peripherals

ARM TrustZone, connecting peripherals?

由 大憨熊 提交于 2019-12-30 05:04:26
问题 I'm currently doing some research about ARM's TrustZone, e.g. here: ARM information center. As far as I understand, with TrustZone a secure environment based on the AMBA AXI bus can be created. On ARM website it says: "This concept of secure and non-secure worlds extends beyond the processor to encompass memory, software, bus transactions, interrupts and peripherals within an SoC." I read that peripherals can be connected to TrustZone via the N on S ecure-bit of the AMBA AXI bus (The extra

How are USB peripherals' bIntervals enforced?

由 只谈情不闲聊 提交于 2019-12-25 02:44:33
问题 I have a FullSpeed USB Device that sends a Report Descriptor, whose relevant Endpoint Descriptor declares a bInterval of 8, meaning 8ms. The following report extract is obtained from a USB Descriptor Dumper when the device's driver is HidUsb: Interface Descriptor: // +several attributes ------------------------------ 0x04 bDescriptorType 0x03 bInterfaceClass (Human Interface Device Class) 0x00 bInterfaceSubClass 0x00 bInterfaceProtocol 0x00 iInterface HID Descriptor: // +bLength, bCountryCode

Casting the results of a volatile expression to void

由 梦想的初衷 提交于 2019-12-24 11:08:24
问题 Note: This is Not the same thing that has been asked many times. Yes I have read the many many posts about casting to void. None of those questions resulted in the answer I suspect is true here. Background info: Embedded C. This is specifically related to memory mapped volatile pointers. In other words, peripheral registers. I came across the following line in a routine that involves writing to an I2C peripheral: (void) I2C1->SR2; I2C1 is #defined as a struct * to volatile memory. So the

BLE peripheral throughput limit

由 拜拜、爱过 提交于 2019-12-18 13:13:18
问题 We are developing a BLE sensor Peripheral to work with an iPad, that requires the following throughput of data on the BLE notification characteristic (no acknowledge) using a TI CC2541 BLE module and a custom profile: One 20 bytes (GATT maximum standard packet) every 10ms, or since we appear to have a limit of 4 packets per connection interval, this equates to one connection interval every 40ms. Throughput required is 2,000 bytes per second, the TI website recommends the CC2541 BLE solution

Bluetooth Peripheral ADVERTISE_FAILED_DATA_TOO_LARGE

由 旧时模样 提交于 2019-12-12 07:14:32
问题 I am trying to advertise in NEXUS 9 and getting the error of ADVERTISE_FAILED_DATA_TOO_LARGE. It was working perfectly fine when I was adding the service after successfully advertising but if I add the service through Advertise Data builder so that other devices can filter while scanning, I get error code 1 i.e ADVERTISE_FAILED_DATA_TOO_LARGE a) Working Code public void startAdvertisingService() { AdvertiseSettings settings = new AdvertiseSettings.Builder() .setTxPowerLevel(AdvertiseSettings

Can BLE iOS device be peripheral and central at the same time?

由 倖福魔咒の 提交于 2019-12-11 04:52:44
问题 Is there any possibility to have both peripheral and central mode available at the same time? In that case we are advertising as peripheral while listening for advertisements of other devices. Thanks 回答1: Yes - You can Althpough the same device being central and peribheral at the same time is not standard as pe Bluetooth current specification, iOS currently supports it 来源： https://stackoverflow.com/questions/14599784/can-ble-ios-device-be-peripheral-and-central-at-the-same-time

Peripheral transmit queue issue

由 ￡可爱￡侵袭症＋ 提交于 2019-12-06 08:38:22
问题 I’m working on a simple wrapper around CoreBluetooth to send any data to any device. During developing I encountered a lot of bugs in framework, they were very annoying and to make my wrapper stable I had to shorten some of functionality for reliability. For now I’m working on sending data from peripheral. Ok, so I have following case: Client asks for value of dynamic characteristic I get a callback on server-side - peripheral:didReceiveReadRequest:. Note : I need to respond to this

Peripheral transmit queue issue

由 和自甴很熟 提交于 2019-12-04 14:28:13
I’m working on a simple wrapper around CoreBluetooth to send any data to any device. During developing I encountered a lot of bugs in framework, they were very annoying and to make my wrapper stable I had to shorten some of functionality for reliability. For now I’m working on sending data from peripheral. Ok, so I have following case: Client asks for value of dynamic characteristic I get a callback on server-side - peripheral:didReceiveReadRequest:. Note : I need to respond to this CBATTRequest in this method - I can’t store it elsewhere and respond to it asynchronously. (Im just putting some

iOS BLE peripheral / advertisement data in background mode

由 我们两清 提交于 2019-12-04 09:25:30
问题 I'm developing a system which has a BLE device (TI CC2540) as Central and an iOS app on iPhone4S as Peripheral. Everything works fine except 1 function I need: white-list (filtering) advertising devices from central side. As far as I know, iOS devices use Random Resolvable MAC address, so we cannot apply white-list based on MAC address. So my current method is: put an ID on "Local name" field on advertisement data of iOS app (iOS device acts as peripheral), Central device will scan and filter

iOS BLE peripheral / advertisement data in background mode

由 情到浓时终转凉″ 提交于 2019-12-03 03:04:02
I'm developing a system which has a BLE device (TI CC2540) as Central and an iOS app on iPhone4S as Peripheral. Everything works fine except 1 function I need: white-list (filtering) advertising devices from central side. As far as I know, iOS devices use Random Resolvable MAC address, so we cannot apply white-list based on MAC address. So my current method is: put an ID on "Local name" field on advertisement data of iOS app (iOS device acts as peripheral), Central device will scan and filter based on retrieved advertisement data. This works unless app is in background. When my app is put in
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