diff --git a/implementation/spi-uwb.tex b/implementation/spi-uwb.tex index cdda2bd3e497a2fedbd64566d535312fea486b51..a15c13efb10e2802ae3925c0229a005af41c76c0 100644 --- a/implementation/spi-uwb.tex +++ b/implementation/spi-uwb.tex @@ -74,11 +74,10 @@ \item \makebox[2cm][l]{SPICLK:} \makebox[2cm][l]{PB10} \end{itemize} - Handling NSS (Slave select) in hardware would be faster and easier. - An undocumented hardware bug in the STMF7-series processor causes the hardware-managed NSS to malfunction if NSS Pulse was disabled. \cite{web:stm_nss_problem} + The NSS pin is handled in software like a standard digital GPIO pin. + Handling NSS (Slave select) in hardware would be faster and easier, however an undocumented hardware bug in the STMF7-series processor causes the hardware-managed NSS to malfunction when NSS Pulse is disabled \cite{web:stm_nss_problem}. An example of NSS Pulse mode can be seen in Figure \ref{pic:NSSP}. The DW1000 does not support NSS Pulse communication, so software NSS was required. - The NSS pin is instead handled like a standard digital GPIO pin. All other SPI is implemented using the HAL\footnote{Hardware Abstraction Layer} libraries supplied by STMicroelectronics for this processor. \begin{figure}[H] @@ -212,7 +211,7 @@ At maximum precision (\SI{0.25}{\degree} resolution and 3 byte per point) a total of $\frac{\SI{270}{\degree}}{0.25} = 1080$ data points, resulting in 3240 bytes of data. This gives \begin{align*} - \frac{1080}{90 / 3} = 36\text{ full packages.} + \frac{1080}{90 / 3} = 36\text{ packets.} \end{align*}