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您好！
目前、我正在使用 TI-SCB 评估 TMAG5170A1器件、使用 Python 脚本(UART、921600)读取数据并将其另存为 MAT 文件。
尽管器件配置为4x - 3.1Ksps (3轴)/25mT / mag_ch_en = 9 (xyz)、但读数速度似乎很低(所有3轴为~500Hz)。 写入器件的寄存器00-03为0x2000、0x25C0、0x0200和0x0000。
我是否可以知道此 EVM 的最大读取速率是多少？
如果需要、可以提供 Python 脚本。
最棒的
套件
您好、Scott、
请检查附件。 有两个线程、一个线程用于 matplotlib 动画(每200ms 刷新一次)、另一个线程用于串行读取和解码。 在 Ctrl+C 之后、脚本将退出并将列表另存为 mat 文件。
import random
from urllib3 import add_stderr_logger
import queue
import matplotlib.animation as animation
import matplotlib.pyplot as plt
import serial
import json
import time
import logging
from time import sleep
import threading
import signal
from scipy.io import savemat
import matplotlib
matplotlib.use('TkAgg')
# plt.switch_backend('agg')
plot_queue = queue.Queue()
plot_start_semaphore = threading.Semaphore(0)
sample_start_sem = threading.Semaphore(0)
will_exit = False
global x_val
global y_val
global z_val
x_val = []
y_val = []
z_val = []
global x_val_all
global y_val_all
global z_val_all
x_val_all = []
y_val_all = []
z_val_all = []
timestamp_nsval = []
# Plot Parameters
mtscale = 25
t_len = 5000 # Number of points to display
y_range = [-1*mtscale, mtscale] # Range of possible Y values to display
z_range = [-1*mtscale, mtscale] # Range of possible Z values to display
fig = plt.figure(figsize=[12, 10], dpi=300)
ax = fig.add_subplot(1, 3, 1)
ay = fig.add_subplot(1, 3, 2)
az = fig.add_subplot(1, 3, 3)
ts = list(range(0, t_len))
xs = [0] * t_len
ys = [0] * t_len
zs = [0] * t_len
lineax = ax.plot(ts, xs)[0]
lineay = ay.plot(ts, ys)[0]
lineaz = az.plot(ts, ys)[0]
try:
s = serial.Serial('COM7', 921600, timeout=1)
except:
raise Exception("serial cannot open")
else:
logging.info("Serial: OK")
# s.close()
def current_milli_time():
return round(time.time() * 1000)
class ReadLine:
def __init__(self, s):
self.buf = bytearray()
self.s = s
def readline(self):
i = self.buf.find(b"\n")
if i >= 0:
r = self.buf[:i+1]
self.buf = self.buf[i+1:]
return r
while True:
i = max(1, min(2048, self.s.in_waiting))
data = self.s.read(i)
i = data.find(b"\n")
if i >= 0:
r = self.buf + data[:i+1]
self.buf[0:] = data[i+1:]
return r
else:
self.buf.extend(data)
def writetmag(tx, reader, addr, value, logprint=None):
# purge all incoming data
lineindex = 0
resp_w = []
addr_strs = "{0:#0{1}x}".format(addr, 4)
value_strs = "{0:#0{1}x}".format(value, 6)
wr_cmd = ('wreg ' + addr_strs + ' ' + value_strs).encode()
try:
tx.write(wr_cmd)
except:
if logprint != None:
logging.info("Writetmag: Error")
else:
# sleep(0.005) # allow all response from write arrive
if logprint != None:
for lineindex in range(3):
resp_w.append(reader.readline())
print(resp_w)
else:
for lineindex in range(3):
reader.readline()
return 0
def readtmag(tx, reader, addr, logprint=None):
addr_strs = "{0:#0{1}x}".format(addr, 4)
rd_cmd = ('rreg ' + addr_strs).encode()
if logprint != None:
print(rd_cmd)
try:
tx.write(rd_cmd)
except:
if logprint != None:
logging.info("Readtmag: Error")
else:
resp_r = reader.readline() # 1st ack
if logprint != None:
print(resp_r)
resp_r = reader.readline() # 2nd val
json_reg_data = json.loads(resp_r)
if ('register' not in json_reg_data):
raise Exception("no key in resp")
resp_r = reader.readline() # 3rd status
return json_reg_data["register"]["value"]
def readtmag_xyz(tx, reader, addr, logprint=None):
addr_strs = "{0:#0{1}x}".format(addr, 4)
rd_cmd = ('rreg ' + addr_strs).encode()
if logprint != None:
print(rd_cmd)
try:
tx.write(rd_cmd)
except:
if logprint != None:
logging.info("Readtmag: Error")
else:
resp_r = reader.readline() # 1st ack
if logprint != None:
print(resp_r)
resp_r = reader.readline() # 2nd val
json_reg_data = json.loads(resp_r)
if ('register' not in json_reg_data):
raise Exception("no key in resp")
resp_r = reader.readline() # 3rd status
if json_reg_data["register"]["value"] > 32768: # means negative
tmag_xyz = (-32768 + (json_reg_data["register"]["value"] - 32768))
else:
tmag_xyz = json_reg_data["register"]["value"]
return tmag_xyz
def animate(i, xs, ys, zs):
if will_exit:
print('sleep 2s')
sleep(2)
plt.close()
else:
plot_start_semaphore.acquire()
xs.extend(x_val)
ys.extend(y_val)
zs.extend(z_val)
sample_start_sem.release()
logging.info("animate: sem post")
# Limit y list to set number of items
xs = xs[-t_len:]
ys = ys[-t_len:]
zs = zs[-t_len:]
# Update line with new Y values
lineax.set_ydata(xs)
lineay.set_ydata(ys)
lineaz.set_ydata(zs)
return [lineax, lineay, lineaz]
def plotter():
# Create figure for plotting
ax.set_ylim(y_range)
ay.set_ylim(y_range)
az.set_ylim(y_range)
# Create a blank line. We will update the line in animate
# Add labels
plt.title('Hall Reading')
plt.xlabel('Samples')
plt.ylabel('Amp')
# Set up plot to call animate() function periodically
ani = animation.FuncAnimation(fig,
animate,
fargs=(xs, ys, zs),
interval=200, # 100ms
blit=True)
plt.show()
def signal_handler(signum, frame):
global will_exit
will_exit = True
def tmag_reader(serial):
reader = ReadLine(serial)
starttime_str = time.strftime("%Y%m%d_%H%M%S")
starttime = time.time_ns()
# try:
while True:
for runtime in range(50):
tmag_x = readtmag_xyz(serial, reader, 0x09) * mtscale / 32768
tmag_y = readtmag_xyz(serial, reader, 0x0A) * mtscale / 32768
tmag_z = readtmag_xyz(serial, reader, 0x0B) * mtscale / 32768
timestamp_nsval.append(time.time_ns() - starttime)
x_val.append(tmag_x)
y_val.append(tmag_y)
z_val.append(tmag_z)
# post a semaphore every 250 samples
plot_start_semaphore.release()
logging.info("sample: sem post")
x_val_all.extend(x_val)
y_val_all.extend(y_val)
z_val_all.extend(z_val)
## generate a dictionary & save
if will_exit:
matdic = {"ts_ns": timestamp_nsval, "x_mt": x_val_all,
"y_mt": y_val_all, "z_mt": z_val_all}
timestr = time.strftime("%Y%m%d_%H%M%S")
filename = 'tmag_' + starttime_str + '-' + timestr + '.mat'
# savemat(filename, matdic)
print('[tmag_reader]: Saved mat file ('+ filename + ')')
break
sample_start_sem.acquire()
x_val.clear()
y_val.clear()
z_val.clear()
print('[tmag_reader]: Thread exit')
if __name__ == "__main__":
cnt_real = 0
cnt = 0
format = "%(asctime)s: %(message)s"
logging.basicConfig(format=format, level=logging.INFO,
datefmt="%H:%M:%S")
# Create figure for plotting
ax.set_ylim(y_range)
ay.set_ylim(y_range)
az.set_ylim(z_range)
# init setup
num_of_line = 3
tstart = time.time_ns()
reader = ReadLine(s)
# a. write 0x2000 to 0x00
writetmag(s, reader, 0x00, 0x2000)
reg_val = readtmag(s, reader, 0x00)
if reg_val != 0x2000:
raise Exception("error in 00")
# b. write 0x25C0 to 0x01 (25mT / xyz / 1000ms sleep)
writetmag(s, reader, 0x01, 0x25C0)
reg_val = readtmag(s, reader, 0x01)
if reg_val != 0x25C0:
raise Exception("error in 01")
# c. write 0x0200 to 0x02
writetmag(s, reader, 0x02, 0x0200)
reg_val = readtmag(s, reader, 0x02)
if reg_val != 0x0200:
raise Exception("error in 02")
# d. write 0x0000 to 0x03
writetmag(s, reader, 0x03, 0x0000)
reg_val = readtmag(s, reader, 0x03)
if reg_val != 0x0000:
raise Exception("error in 03")
# start conversion
# e. write 0x2020 to 0x00
writetmag(s, reader, 0x00, 0x2020)
reg_val = readtmag(s, reader, 0x00)
# add a signal handler for capturing Ctrl+C
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)
if reg_val != 0x2020:
raise Exception("error in 00")
try:
x = threading.Thread(target=tmag_reader, args=(s,))
# x.daemon = True
x.start()
except:
raise Exception('fail to create thread')
# Create a blank line. We will update the line in animate
# Add labels
plt.title('Hall Reading')
plt.xlabel('Samples')
plt.ylabel('Amp')
# Set up plot to call animate() function periodically
ani = animation.FuncAnimation(fig,
animate,
fargs=(xs, ys, zs),
interval=20, # 100ms
blit=True)
plt.show()
x.join()
tstop = (time.time_ns() - tstart) / 1000000
s.close()
exit()
谢谢、祝您顺利。
套件
套件、
根据您的代码、您似乎正在使用标准 USB 通信来实现读取。 遗憾的是、标准控制接口无法以传感器的最大采样率发送 SPI 事务。 在 EVM GUI 上、这种数据传输模式也会经历相同的延迟。 为了提高吞吐量、TI-SCB 能够实现大容量 USB 数据通信。 您需要设置 Python 代码、以便首先作为批量器件连接到 EVM。
本用户指南中提供了有关如何将此模式与 TI-SCB 搭配使用的更多指导：
https://www.ti.com/lit/ug/sbou241d/sbou241d.pdf#page=20
本用户指南中显示的标志反映了 INA228所需的内容。 对于 TMAG5170、这些标志定义如下：
XAXIS = 0b10000000；
YAXIS = 0b01000000；
ZAXIS = 0b00100000；
温度 = 0b00010000；
角度 = 0b00001000；
幅度 = 0b00000100；
此外、INA228支持以菊花链方式连接多个器件。 对于 TMAG5170、通道地址 ID 和 numDevices 应设置为1。
数据将在必须解析的数据包中返回。 我已经了解了如何在已发布的 GUI 中完成此操作：
packetHandler: function (rxData) {
// Accumulate data
// CONSIDER: Checking if we are receiving more bytes than expected
//console.log(`${rxData.data.length} bytes comming in`);
rxData.data.forEach(byte => {
this.packetData[this.byteCount++] = byte;
if(this.byteCount > this.packetData.length)
{
console.error(this.is, `packetData overflow! (packet length: '${this.packetData.length}', byte count: '${this.byteCount}')`);
}
if(this.packetData.length === this.byteCount)
{
if(templateObj.$.ti_widget_checkbox_autoCollect.checked && numSamplesCollected >= templateObj.$.ti_widget_numberbox_samples_all.value)
{
this.fire('abort-collect');
}
else
{
this.dataParser();
}
this.byteCount = 0;
numSamplesCollected++;
}
});
// Debugging...
//console.log(rxData);
},
dataParser: function () {
let index = 0;
//.log(`parsing data`);
while (index < this.packetData.length) {
//Format: Frame ID, Address, Data
// Check for frame ID and two data bytes
if (this.packetData[index] !== 0x00) {
console.error(this.is, `USB data misaligned - Cannot parse! (Index: '${index}', Value: '${this.packetData[index]}')`);
this.fire('abort-collect');
index++; //needed?
return;
}
index++;
// let decimal = (this.packetData[index + 1] << 8) | this.packetData[index + 2]; // Unsigned
// if (!this.isADS1118) { decimal = this.signExtend(decimal >> 4, 12); } // ADS1018 (ADC + Temp sensor): 12-bit left-aligned data
// else if (isTempMode) { decimal = this.signExtend(decimal >> 2, 14); } // ADS1118 (Temp sensor): 14-bit left-aligned data
// else { decimal = this.signExtend(decimal, 16); } // ADS1118 (ADC data): 16-bit data
// this.channelData.push(decimal);
// index += 3;
let Address = this.packetData[index++];
let Data = this.packetData[index++];
let RegisterSize = 2;//bytes
if (templateObj.$.ti_widget_checkbox_XAXIS.checked) //X
{
CHX = 0;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_label = "X-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_color = "#00BBCC"
if (templateObj.$.ti_widget_checkbox_YAXIS.checked) //XY
{
CHY=1;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_label = "Y-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_color = "#115566";
if (templateObj.$.ti_widget_checkbox_ZAXIS.checked) //XYZ
{
CHZ=2;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_2_label = "Z-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_2_color = "#AAAAAA";
}
else {CHZ = -1;}
}
else
if (templateObj.$.ti_widget_checkbox_ZAXIS.checked) //XZ
{
CHY=-1;
CHZ=1;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_label = "Z-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_color = "#AAAAAA";
}
else //X only
{
CHY=-1;
CHZ=-1;
}
}
else //No X
{
CHX = -1;
if (templateObj.$.ti_widget_checkbox_YAXIS.checked)
{
CHY = 0;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_label = "Y-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_color = "#115566";
if (templateObj.$.ti_widget_checkbox_ZAXIS.checked)
{
CHZ=1;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_label = "Z-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_1_color = "#AAAAAA";
}
else {CHZ = -1;}
}
else
{
CHY = -1;
if (templateObj.$.ti_widget_checkbox_ZAXIS.checked)
{
CHZ = 0;
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_label = "Z-Component";
templateObj.$.ti_widget_scalargraph_MAGFIELD.series_0_color = "#AAAAAA";
}
else {CHZ=-1;}
}
}
for(let i = 1; i < RegisterSize; i++)
{
Data = (Data << 8) | this.packetData[index++];
}
let temp = Data;
if(Address === 0x9 || Address === 0xA || Address === 0xB) //X,Y,Z
{
if(Data >= 0x7FFF)
{
Data = Data - 0x10000;
}
let maxVal = 32767;
let minVal = -32768;
if(Data > maxVal) {Data = -Data/minVal;}
else{Data = Data/maxVal;}
let ChannelID;
if (Address === 0x09)
{
ChannelID = CHX;
Data = Data * adcrange[0];
}
else if (Address === 0x0A)
{
ChannelID = CHY;
Data = Data * adcrange[1];
}
else if (Address === 0x0B)
{
ChannelID = CHZ;
Data = Data * adcrange[2];
}
//put data into plot
if(templateObj.$.ti_widget_scalargraph_MAGFIELD[`value_${ChannelID}`] === Data)
{
if(ChannelID === 0)
{
templateObj.$.ti_widget_scalargraph_MAGFIELD.value_0Changed();
}
else if(ChannelID === 1)
{
templateObj.$.ti_widget_scalargraph_MAGFIELD.value_1Changed();
}
else if(ChannelID === 2)
{
templateObj.$.ti_widget_scalargraph_MAGFIELD.value_2Changed();
}
}
else
{
templateObj.$.ti_widget_scalargraph_MAGFIELD[`value_${ChannelID}`] = Data;
}
}
else if(Address === 0xC) //DIE TEMP
{
//Data = 65/256*(Data/16-1066)+25;
let T0 = 25;//Ref temp
let ADCT0 = 17522;//ADC value at T0
let TRES = 60; //LSB per C
Data = T0 + (Data-ADCT0)/TRES;
//optionally convert to F
if(ti_widget_droplist_dietemp_unit.selectedText == "°F")
{
Data = (Data * (9/5)) + 32;
}
if(templateObj.$.ti_widget_scalargraph_DIETEMP.value_0 === Data)
{
templateObj.$.ti_widget_scalargraph_DIETEMP.value_0Changed();
}
else
{
templateObj.$.ti_widget_scalargraph_DIETEMP.value_0 = Data;
}
}
else if(Address === 0x13) //ANGLE
{
let fraction = Data & 0xF;
Data = Data >> 4;
Data = Data + fraction/16;
if(templateObj.$.ti_widget_scalargraph_ANGLE.value_0 === Data)
{
templateObj.$.ti_widget_scalargraph_ANGLE.value_0Changed();
}
else
{
templateObj.$.ti_widget_scalargraph_ANGLE.value_0 = Data;
}
}
else if(Address === 0x14) //Magnitude
{
let result = Data;
let maxVal = 32767; //use xyz chanel max val, for scale
let mRange;
if('ti_model_register.sensor_config_register.angle_en' == 2 )
{
mRange = adcrange[1];
}
else
{
mRange = adcrange[0];
}
Data = 16*Data*mRange/maxVal; //multiply by 16 for magnitude conversion (from 12 bit xyz chanel values)
if(templateObj.$.ti_widget_scalargraph_MAGNITUDE.value_0 === Data)
{
templateObj.$.ti_widget_scalargraph_MAGNITUDE.value_0Changed();
}
else
{
templateObj.$.ti_widget_scalargraph_MAGNITUDE.value_0 = Data;
}
}
// Debugging...
//console.log(this.channelData);
}},
希望这能帮助您整理连接、以便能够以最大速率收集数据。
谢谢、
Scott